RELISHED   IN   NEW  YORK.  1834  ESTABLISHED   IN   SAN   FRANCISCO,  1855 


ILLUSTRATED  CATALOGUE  AND  MANUAL 


OF 


CIVIL  ENGINEERS' 


AND 


PURVEYORS'  INSTRUMENTS:; 

(With  Useful  Tables,  Illustrations  and  Descriptions  of  the  Latest 
Improvements   on   the   Most    Recent   Instruments   of   Precision.) 


MANUFACTURED  BY 


J.  C.  SAhA 


SUCCESSOR   TO 


JOHN     ROBCH 

429  MONTGOMERY  ST.,  Cor.  Sacramento  ~ 

SAN    1 


1896 
fy    PRICE,    FIFTY    CENTS 


TF^TIMOMIAI 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

OIKT  OF" 


Received 
Accession  No. 


3/    -   Class  No. 


sir*} 


SillCC   1865,  tJlC   TTfcchanics'  institute  of  tSan    Francisco 

//us  awarded  me 

8  Gold  Medals 

4  Grand  Silver  Medals 

1  Grand  Bronze  Medal 
8  Silver  Medals 

and  6  Diplomas 

for  the  best  Surveying'  and  l^iginccrhi^    Instruments^ 
Altitude  Barometers  and  Drawing  Instruments. 

I  also  received 

3  Gold  Medals  and  1  Diploma  of  Honor 

at  the 
California   Sntcrnationai    TTfidiuintcr    Exposition, 


There  arc  on  file  in  mv  office,  hundreds  of  unsolic- 
ited testimonials  which  all  parties  i  tit  crested  in  such 
matters  arc  free  to  read  at  anv  time. 


OSTABLISHED   ,N   NEW   YORK,    1X11  ESTABLISHED   ,N   SAN    FRANC.SCO,   1S55 


ILLUSTRATED  CATALOGUE  AND  MANUAL 


OF 


CIVIL   ENGINEERS' 


AND 


SURVEYORS'  INSTRUMENTS 

(With  Useful  Tables,  Illustrations  and  Descriptions  of  the  Latest 
Improvements   on   the   Most    Recent   Instruments   of   Precision.) 


MANUFACTURED  BY 


J.  C.  SAhA 


SUCCESSOR   TO 


CH 


429  MONTGOrvTBe^ST.,  Cor.  Sacramento 
SAN    FRANCISCO,   CAL. 


1896 
PRICE,     FIFTY     CENTS 


SUBDIVISIONS 


/ 

Introduction,  ...  (> 

Preface, 

Part  A — Surveyors'    and   Engineers'   Instruments    for 

Field  Work,  ...  23 

Part  B — Surveyors'     Engineers'     Architects'     and 

Draughtsmen's  Office  Requisites,         .  (.M 

Part  C — Miscellaneous  Scientific  Instruments,  101 

Part  D— Papers  and  Tables,          .  .  107 


J.    C. 

429  Montgomery  Street,  San  Francisco,  Cal. 


TO    CORRESPONDENTS 


This  catalog-lit'  and  price  Us!  supersedes  all  former  editions. 

The  prices  hi  this  catalogue  are  net  cash,  and  instruments  are  not 
sold  on  the  installment  plan. 

Every  instrument  is  carefully  packed,  and  the  responsibility  of  the 
house  ceases  when  instruments  leave  the  factory.  In  case  of  damage,  the 
express  companies  must  be  held  liable. 

Instruments  are  not  sent  on  trial  but  will  be  sent  (\  ().  /).  for  pur- 
poses of  examination. 

Goods  sent  C.  O.  D.  only  when  order  is  accompanied  bv  a  deposit 
sufficient  to  pay  expressage  both  ways. 

7 he  engravings  in  this  catalogue  give  a  good  idea  of  the  instru- 
ments at  the  present  time;  as  improvements  however,  are  being  constantly 
made,  customers  will  always  receive  the  latest  improved  instruments. 

Mv  aluminum  instruments  weigh  from  jo  to  50%  less  than  the  reg- 
ular ones,  and  the  price  is  15%  higher. 

II  'eight  of  regular  instruments  are  as  follows: 


Transits,  No.... 

1                2 

3 

4 

5 

6               7 

14^  Ibs.       15 

16 

17 

11 

10            17  '4 

Tripods  

...8K              M 

sy2 

8^ 

7 

7               8'< 

Levels  

...8  Ibs.           9 

10 

11 

15                12|< 

10 

8 

Tripods  

...  8><              8^ 

8  '4 

8 

Any  extras  to  transits  and  levels  supplied  at  the  lowest  rates. 
The  illustrations  of  transits,  levels  and  other  surveying  instruments 
in  this  catalogue,  represent  instruments  made  exclusively  in  my  shop. 

Standard  astronomical  instruments  and  other  instruments  not  illus- 
trated in  this  catalogue,  are  kept  in  stock  and  can  be  furnished  upon 
application.  Having  made  arrangements  with  foreign  makers  of  such 
instruments,  I  can  supply  them  upon  the  most  reasonable  terms. 


INTRODUCTION 


In  addition  to  the  long  personal  experience,  indispen- 
sable to  the  manufacturer,  and  the  trained  staff  of  work- 
men engaged  in  the  delicate  task  of  building  surveying 
and  engineering  instruments,  and  automatic  machinery 
of  precision,  it  is  absolutely  necessary  to  build  such 
instruments  so  as  to  conform  with  the  mathematical 
exactions  required  to  perform  correct  work  in  the  field 
and  office. 

The  following  illustrations  will  give  an  idea  of 
the  most  prominent  o?ies  amongst  those  in  use  in  my 
well-supplied  workshop. 


••i 


PREFACE 


WHEN  JOHN  ROACH,  the  founder  of  this  house,  commenced 
business  in  New  York  City  in  1834,  the  American  Transit 
was  only  three  years  old.  Proper  castings  were  difficult  to  obtain,  and 
the  instrument-maker  at  that  time  worked  under  many  disadvantages. 
There  were  no  lenses  made  in  the  United  States  suitable  for  surveying 
instruments,  and  until  about  1850,  when  an  instrument  was  ordered, 
the  telescope  had  to  be  made  to  suit  the  glasses  obtainable.  About  the 
latter  date,  good  glasses  of  American  make  commenced  to  appear,  and 
there  was  a  noticeable  improvement  in  the  making  of  transits;  some- 
thing like  uniformity  in  size  and  make  was  obtainable. 

In  1855  Mr.  Roach  established  himself  in  San  Francisco,  and  the 
( '  Roach  Instruments ' '  became  known  in  the  West  wherever  the  sur- 
veyor pitched  his  camp.  Some  of  the  first  made  are  in  use  to  this  day 
and  there  is  no  sign  of  breaking  down  yet;  they  have  naturally  an  aged 
appearance,  but  their  joints  are  in  fairly  good  order,  their  graduations 
clear,  and  the  glasses  nearly  perfect. 

Instruments  in  the  early  days  were  not  handled  always  by  the 
most  competent  men  and  received  harder  usage  than  modern  instru- 
ments are  called  upon  to  stand;  as  a  consequence,  metal  was  not  spared 
in  their  construction.  While  lightness  was  always  a  desideratum,  still 
strength  was  more  important,  and  the  early  instruments  were  strong. 
They  had  also  an  appearance  of  strength  and  solidity  which  favorably 
impressed  members  of  the  engineering  profession. 

The  modern  instrument,  made  by  this  house,  while  changed  in 
appearance  somewhat  to  suit  the  eyes  of  the  present  day  user,  still  pre- 
serves the  sturdy,  well-made,  substantial  appearance  which  did  so  much 
to  render  popular  the  "  Roach  Instrument."  Although  it  has  a  strong 
appearance,  and  is  in  fact  as  strong  as  any  instrument  need  to  be,  it 
weighs  no  more  than  one  of  the  same  size  made  by  any  other  maker. 
Strength  is  secured  by  a  system  of  bracing  and  ribbing,  which  enables 
a  saving  in  much  material.  lightness  is  secured  by  this  same  system 
of  ribbing  and  also  by  the  use  of  aluminum  alloy  in  all  places  where  it 
is  of  undoubted  benefit. 

In  examining  this  catalogue  the  reader's  attention  is  directed  to 
the  sturdy  appearance  of  the  instruments  and  to  the  weight  of  each. 
He  must  remember  also  that  they  represent  an  evolution,  the  result  of 
a  growth  of  over  forty  years  of  experience  on  the  Pacific  Coast  in  all 
classes  of  work. 

/.    C.    SAL  A. 


ILLUSTRATED   CATALOGUE   OF 


MAKING    AND    REPAIRING    OF 
INSTRUMENTS 


The  first  essential  for  accurate  work  with  any  kind  of  an  instru- 
ment is  that  it  be  carefully  made  of  the  best  materials  and  that  the 
workmanship  be  the  best  obtainable. 

These  desirable  results  have  been  reached  in  my  instruments. 
Only  the  best  materials  are  used,  and  the  workmen  are  all  first-class 
men  of  long  experience  and  special  training.  The  tools  used  are  of  the 
strongest  and  most  modern  construction.  The  instruments  for  precise 
work  are  automatic  and  of  the  most  approved  types. 

The  illustrations  give  a  good  idea  of  the  various  departments  of 
the  establishment,  and  a  visit  to  the  works  will  well  repay  those  who 
are  sufficiently  interested  to  call.  I  am  always  pleased  to  see  my  patrons 
and  friends. 

Attention  is  called  to  the  cuts  of  the  dividing  engine  and  other 
tools  I  use. 

As  remarked  in  the  preface,  my  instruments  are  strong  and  as 
light  as  is  consistent  with  proper  strength.  The  dead  weight  is  removed 
wherever  not  necessary  for  stiffness;  at  the  same  time,  stiffness  is 
secured  by  properly  shaping  the  parts.  Each  part  is  shaped  to  with- 
stand the  strains  it  will  be  called  upon  to  bear,  and  wherever  possible 
to  remove  extra  metal  it  has  been  done,  but  ribs  have  been  left.  A 
judicious  employment  of  aluminum  alloy  having  a  great  tensile  strength 
helps  to  decrease  the  weight  materially,  and  all  bearing  parts  are  of  the 
hardest  metals.  Joints  have  been  avoided  largely  by  combining  as 
many  parts  as  possible  in  a  single  casting.  This,  while  an  increased 
expense  in  making,  is  of  great  value,  for  it  reduces  the  number  of  joints 
and  therefore  the  weak  places. 

ALUMINUM. — A  great  popular  demand  has  of  late  years  arisen 
for  instruments  made  of  aluminum,  and  in  response  to  the  demand,  I 
make  instruments  with  a  very  large  percentage  of  aluminum  when 


J.    C.    SALA,    SAN    FRANCISCO  II 


ordered.  These  instruments  are  lighter  than  the  regular  make,  and 
the  dull  silver-like  finish  is  very  pleasing.  The  workmanship  on  them 
is  of  the  same  high  class  as  on  my  other  instruments,  and  the  customer 
secures  a  good  instrument  subject  however  to  the  advantages  and  dis- 
advantages mentioned  below. 

The  disadvantages  of  aluminum  are  its  softness,  the  difficulty  of 
soldering  to  other  metals  and  its  wearing.  On  the  other  part  there  are 
incontestable  advantages  for  certain  parts  of  instruments  where  light- 
ness is  especially  desired. 

The  aluminum  bronze  is  now  considered  one  of  the  best  materials 
entering  into  the  manufacture  of  tubes  for  telescopes,  on  account  of  the 
great  rigidity  of  this  alloy.  Alloy  of  silver  and  aluminum  is  certainly 
a  valuable  material  for  graduation,  allowing  an  easier  reading  than  on 
pure  silver.  I  have  been  building  such  parts  of  aluminum  or  aluminum 
alloys  on  transits,  levels  and  plane  tables  where  the  metal  and  its  alloys 
are  of  recognized  advantage,  and  have  such  instruments  on  hand,  but 
am  opposed  to  an  indiscriminate  use  of  this  metil  in  the  construction  of 
instruments  of  precision. 

In  regard  to  aluminum  for  surveying  instruments,  a  great  many 
unwarranted  statements  are  made  every  day  and  engineers  should 
understand  fully  this  question.  Aluminum  while  a  very  light  metal, 
is  not  a  non-friction  metal  by  any  manner  of  means.  The  co-efficient 
of  friction  is  very  high,  therefore  for  all  the  finer  bearing  parts  a  bush- 
ing of  hard  metal  must  be  used,  otherwise  the  close  fitting  of  parts  so 
necessary  to  the  instrument  of  precision  is  lacking.  A  transit  contain- 
ing enough  aluminum  to  reduce  the  weight  very  considerably,  is  com- 
posed of  too  many  parts  to  be  a  satisfactory  instrument.  I  use  enough 
aluminum  alloy  in  my  instruments  to  lighten  some  of  the  more  unim- 
portant parts,  but  it  is  confined  to  such  parts. 

An  instrument  must  be  steady  and  should  have  enough  weight  to 
secure  such  steadiness  as  will  enable  it  to  stand  wind  well.  The  surface 
exposed  to  the  wind  is  considerable,  and  the  wind  exercises  much  force 
upon  it.  If  the  instrument  is  therefore  very  light  it  will  tremble  in  a 
breeze.  Instruments  made  of  extreme  lightness  must  have  heavy 
tripods  and  it  is  difficult  to  see  where  the  advantage  of  the  light  top 
comes  in  in  such  case.  If  an  engineer  really  desires  to  carry  a  light 


12  ILLUSTRATED   CATALOGUE   OF 

instrument  it  will  be  better  to  purchase  a  small  sized  transit  than  a 
large  one  so  light  that  it  will  be  an  annoyance  to  use  it. 

I  have  carefully  experimented  with  the  various  alloys  of  alumi- 
num, and  as  a  result  of  these  experiments  believe  it  is  not  of  such 
value  as  to  justify  its  very  extensive  use  in  surveying  instruments. 

The  best  alloys  of  metals  are  used,  and  such  as  have  nearly  the 
same  co-efficient  of  expansion  as  glass  are  the  preferable,  as  the  optical 
parts  of  instruments  are  of  such  importance.  The  co-efficient  of  glass 
per  linear  foot  for  one  degree  Fahrenheit  is  0.000054  inches;  of  steel  it 
is  0.000076;  brass,  0.000125;  aluminum,  0.000148.  It  may  be  readily 
seen  that  when  an  instrument  is  so  made  that  all  its  parts  have  the 
same,  or  nearly  the  same,  co-efficient  of  expansion,  that  it  will  retain 
its  adjustments  under  decided  changes  of  temperature  much  better  than 
one  which  has  various  metals  with  widely  differing  co-efficients.  Alum- 
inum is  the  least  desirable  of  metals  in  use  for  such  purpose.  Iron  and 
steel  of  course  would  be  better  than  brass  were  it  not  for  the  needle  and 
also  the  liability  to  rust  in  exposed  positions.  Steel  centers  for  levels 
are  much  used  now  and  have  their  advantages.  I  put  them  in  when 
ordered  in  place  of  ordinary  centers  without  extra  charge. 

FINISH. — The  finish  of  my  instruments  is  of  a  pleasing  brown 
color,  unless  ordered  otherwise.  I  finish  the  instruments  in  any  manner 
ordered. 

The  natural  finish  of  bronze  or  any  other  alloy  or  metal  has  a 
glaring  effect  upon  the  eye  of  the  observer,  and  is  therefore  objection- 
able. The  black  finish  is  not  to  be  recommended  on  account  of  its 
great  affinity  for  absorbing  heat  and  consequently  expanding  the  more 
exposed  parts  of  the  instrument  very  rapidly  to  the  detriment  of  the 
adjustments.  To  obviate  these  inconveniences  I  have  adopted  two 
styles  of  finish  which  have  given  the  best  possible  results. 

My  bright  finish,  somewhat  the  color  of  antique  bronze,  is  not 
glaring  and  stands  well  any  wear.  My  cloth  finish  on  such  parts  of 
the  instruments  as  are  apt  to  absorb  the  heat  more  rapidly  on  account 
of  their  exposure,  is  of  a  pleasant  greenish  color,  and  feels  to  the  touch 
as  a  soft  piece  of  cloth.  It  secures  a  very  gradual  and  uniform  expan- 
sion and  contraction  in  sudden  changes  of  temperature.  The  dura- 
bility of  this  finish  is  not  equal  to  the  bright  finish,  but  lasts  about  as 


j.  c.  SALA,  SAN  FRANCISCO  13 


long  as  the  black  finish  would.  As  it  is  not  necessary  to  finish  or 
polish  an  instrument  so  finely  when  cloth-finished,  the  cost  is  less  than 
for  the  ordinary  bright  finish.  In  neither  of  my  finishes  enter  any 
material  having  effect  upon  the  magnetic  needle. 

My  instruments  do  not  separate  above  the  levelling  screws  but  are 
placed  in  the  case  directly  and  in  an  upright  position.  The  cases  have 
rubber  cushions  on  the  bottom  to  ease  all  jarring  motion  in  transpor- 
tation. 

It  ma}^  be  seen  that  the  constant  endeavor  of  this  house  is  to 
maintain  its  old  reputation  for  furnishing  the  engineer  with  an  instru- 
ment he  can  rely  upon.  I  desire  to  make  at  all  times  an  instrument 
which  will  need  no  special  puffing  or  advertising,  but  will  be  its  own 
recommendation. 

To  secure  these  desirable  ends,  special  attention  is  paid  to  secure: 

i st  -Careful  workmanship  and  design. 

2d  —  Accuracy  of  division. 

3d  —  High  powered  achromatic  telescopes. 

4th — Equable  adj  ustments. 

5th — Lightness,  stiffness  and  strength. 

6th     Simplicity  in  parts. 

These  all  conduce  to  ease  in  manipulation  and  certainty  in  results. 

Every  instrument  sent  from  the  factory  is  carefully  adjusted  and 
packed  in  a  manner  which  should  insure  safe  transportation.  My 
experience  in  packing  instruments  for  so  many  years  when  they  were 
exposed  to  all  sorts  of  usage  in  transportation,  has  developed  skill  in 
packing,  and  very  few  instruments  sent  by  me  arrive  at  their  destina- 
tion with  the  adjustments  impaired  in  the  slightest  degree. 

REPAIR  OF  INSTRUMENTS. — My  facilities  for  repair  work  of  all 
kinds  are  unsurpassed.  Having  been  for  years  the  only  house  on  the 
Coast  in  this  line,  and  the  freight  rates  to  the  East  being  very  high, 
I  have  repaired  instruments  of  nearly  every  known  make.  I  am 
therefore  as  familiar  with  the  construction  and  workmanship  of  the 
leading  instrument  makers  of  this  country  as  with  my  own  make, 


14  ILLUSTRATED    CATALOGUE   OF 


and  can  guarantee  satisfaction  in  repairing.  My  shop  is  especially 
well  fitted  for  such  work. 

The  most  satisfactory  way  to  obtain  first-class  work  in  repairs  is 
to  send  the  instrument  to  me  with  instructions  to  put  it  in  thorough 
order  and  adjustment.  I  will  give  an  estimate  of  the  cost  if  desired, 
before  doing  the  work.  Of  course  this  is  the  most  expensive  way  of 
doing  the  work  but  it  is  the  cheapest  in  the  end.  If  it  is  not  thought 
best  to  do  this,  the  instrument  can  be  sent  with  a  clear  description  of 
the  repairs  or  other  work  desired,  and  I  will  follow  instructions.  I  will 
do  as  good  work  as  can  be  done,  taking  into  account  the  make,  material, 
workmanship  and  general  state  of  the  instrument  as  regards  condition 
and  extent  of  the  damage  done.  The  cost  will  be  as  low  as  is  consis- 
tent with  good  work  and  will  be  according  to  the  time  consumed  and 
material  used. 

The  packing  of  instruments  sent  for  repairs  should  be  carefully 
attended  to.  Place  the  instrument  in  its  own  case  and  then  the  case 
into  a  packing  box  with  the  space  between  filled  with  excelsior  or  straw. 
This  will  enable  it  to  be  .sent  safely  and  at  the  same  time  enables  it  to 
be  shipped  at  regular  rates.  Usually  higher  rates  are  charged  for  sur- 
veying instruments  than  for  ordinary  express  packages. 

I  will  guarantee  as  good  work  as  it  is  possible  to  put  on  the  job, 
but  reserve  the  right  to  decline  a  job  if  I  believe  it  impossible  to  put 
the  instrument  into  such  shape  as  will  warrant  the  owner  spending  the 
money  on  it. 

My  own  instruments  should  always  be  sent  to  me  for  repairs,  as 
by  so  doing,  considerable  expense  may  be  saved.  I  am  in  a  position  to 
duplicate  all  parts  from  stock  on  hand  and  can  therefore  repair  instru- 
ments of  my  own  make  quickly  and  cheaply. 


J.    C.    SALA,    SAN   FRANCISCO 


THE    AUTOMATIC    DIVIDING    ENGINE. 

30-INCH   CIRCLE 

This  Engine   is  Used  to   Make  Graduations  on  Limbs,  Verniers,  Etc., 
and  is  One  of  the  Best  ever  Built  in  this  Country  or  Europe. 


i6 


ILLUSTRATED   CATALOGUE   OF 


APPARATUS    FOR    TESTING    MAGNETIC    INFLUENCE    OF    METAL. 


CENTERING   APPARATUS -USED    FOR    TESTING   GRADUATIONS. 


J.    C.    SALA,    SAN    FRANCISCO 


THE    LONGITUDINAL    DIVIDING    ENGINE. 

Apparatus  for  Graduating-  the  Grooves  for  Cross  and  Stadia  Wires 
on    the   Diaphragm   of  Telescopes. 


THE    COLLIMATOR    APPARATUS. 
For  Adjusting  the  Line  of  Collimation  of  Surveying-  Instruments. 


i8 


ILLUSTRATED    CATALOGUE   OF 


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J.    C.    SALA,    SAN    FRANCISCO 


THE    COLLAR    TESTER. 

Used  in   the  Construction  of  Levels,   to  Ascertain  the  Uniformity  of 
Collars  on  Telescopes. 


CARE    OF    INSTRUMENTS. 


In  the  care  of  instruments,  common  sense  should  play  a  great  part. 

The  tripod  legs  should  never  be  permitted  to  become  loose,  but 
the  nuts  and  bolts  should  fit  snugly.  Before  carrying  the  instrument, 
care  should  be  taken  that  it  is  screwed  firmly  to  the  tripod  and  in  no 
danger  of  falling  off.  It  is  well  also  to  see  that  it  is  tight  before  using 
the  instrument. 

Before  carrying  the  instrument,  the  levelling  screws  should  be 
screwed  to  a  firm  seat  and  the  instrument  slightly  clamped  in  order  to 
prevent  any  movement  or  wear  of  the  centers. 

The  needle  should  always  be  clamped,  except  of  course  when  in 
use.  It  is  also  thought  well  to  permit  the  needle  to  swing  freely  when 
the  instrument  is  in  its  case,  as  it  will  swing  at  once  into  the  meridian 
in  which  position  it  is  supposed  to  retain  magnetism  best. 

All  unnecessary  movement  on  the  pivot  should  be  avoided,  and 
when  swinging,  the  motion  should  be  gently  checked  by  the  lifter  in 
order  to  reduce  the  play  to  as  small  an  arc  as  possible.  The  needle 
should  always  be  gently  let  down  on  the  pivot. 

A  silk  handkerchief  should  never  be  used  to  clean  the  glass  or 
lenses  of  a  transit. 


20  II^USTRATKD  CATALOGUE  OF 

Buttons,  knives,  keys,  wire  hat  brims,  cheap  watch  chains,  etc., 
have  a  great  effect  on  the  needle  of  an  instrument. 

Screws  should  never  be  turned  more  than  necessary  to  obtain  a 
firm  seat.  The  slightest  movement  more  will  strain  them  and  impair 
the  accuracy  of  the  instrument  and  reliability  of  adjustment.  A  screw 
should  never  be  so  tight  that  any  great  effort  will  be  necessary  to 
start  it.  When  the  threads  of  a  screw  work  hard,  they  should  be 
cleaned  with  a  stiff  bristle  brush.  A  tooth  brush  is  excellent.  After 
cleaning  the  threads  with  the  brush,  oil  the  screw  and  work  it  in  to  its 
full  length  and  then  out  again ;  the  oil  should  be  wiped  off  with  a  clean 
chamois  skin  and  more  oil  put  on  and  the  screw  again  worked  in  and  out. 
This  operation  should  be  repeated  again  and  again  until  the  screw  is 
clean  and  works  smooth  and  free.  When  this  result  is  accomplished, 
the  screw  should  be  run  in  and  out  several  times  without  oil  and  wiped 
each  time  to  remove  all  oil.  No  oil  should  be  left  on  exposed  portions 
of  levelling  or  tangent  screws,  as  it  will  collect  dust. 

A  gossamer  or  silk  water-proof  bag  should  be  carried  in  the  field 
for  the  purpose  of  covering  the  instrument  in  case  of  rain  or  dust 
storms  coming  up. 

The  only  oil  to  be  used  on  an  instrument  is  the  very  best  quality 
of  watch  oil  and  as  little  of  that  as  is  necessary  to  cause  a  smooth 
motion  of  the  parts  lubricated;  too  much  will  cause  the  parts  to  become 
sticky  and  gum  up.  Sometimes  marrow  is  used  for  lubricat- 
ing, but  it  is  objectionable  because  it  is  liable  to  become 
rigid  and  bind  in  cold  weather.  Vaseline  is  very  good,  as  it  is  less 
rigid  than  watch  oil  and  somewhat  softer  and  less  liable  to  bind  than 
marrow,  but  it  requires  renewal  often.  As  an  instrument  should  be  as 
little  disturbed  as  possible  in  its  adjustments,  the  best  lubricating 
material  is  that  which  requires  little  attention  and  contains  no  grit. 
Watch  oil  is  the  best  and  is  the  only  thing  to  use  on  centers  and  the 
finer  grade  of  instruments. 

Sea  air  has  a  tendency  to  destroy  the  finish  of  the  surface  of  an 
instrument;  a  good  plan  to  follow  when  working  near  the  seashore  is 
to  cover  the  entire  surface  with  a  thin  coating  of  oil. 

All  exposed  surfaces  moving  in  contact,  such  as  the  object  slide, 
etc.,  must  be  kept  free  from  oil,  as  it  will  collect  dust  and  sooner  or 


J.    C.    SALA,    SAN   FRANCISCO 


later  cause  fretting.  When  any  surface  begins  to  fret,  it  should  be 
carefully  examined  and  a  piece  of  hard  wood  rubbed  on  the  spot  to 
smooth  oif  the  roughness.  If  tin.:  does  not  improve  the  matter,  the 
surface  should  be  slightly  scraped  with  a  sharp  knife  or  touched  with 
a  very  fine  flat  file  and  burnished  with  a  polished  piece  of  steel.  A 
little  oil  can  then  be  applied  and  the  movement  tested.  If  all  fretting 
has  disappeared  the  oil  should  be  very  thoroughly  wiped  off  and  the 
parts  replaced  in  position. 

If  any  powder  is  used  to  reduce  the  roughness  instead  of  employ- 
ing a  scraper,  care  should  be  taken  that  it  is  not  emery,  as  that  is 
the  worst  possible  thing  to  use.  Only  powdered  pumice  or  some  rouge 
should  be  used. 

The  telescope  glasses  should  be  left  in  their  places  as  long  as  it  is 
possible  to  use  them,  as  any  unscrewing  will  destroy  their  seat  and  the 
adjustment  will  be  impaired.  When  the  glasses  however  become 
greatly  soiled  and  it  is  hard  to  get  a  good  sight  through  them  they 
should  be  washed  with  alcohol.  Chamois  skin  and  soft  flannel  are  the 
best  things  with  which  to  wipe  lenses.  Too  much  rubbing  of  lenses 
will  destroy  the  fine  polish  of  the  faces  which  it  is  important  to  preserve 
and  all  unnecessary  rubbing  is  to  be  avoided. 

When  the  graduations  become  greasy,  coat  them  with  a  thin  cov- 
ering of  watch  oil  and  let  it  stand  for  an  hour  or  two;  then  wipe  it 
gently  with  a  piece  of  soft  cloth  or  chamois  and  be  careful  to  take  off 
all  the  oil.  Try  and  avoid  as  much  as  possible,  touching  the  edges  of 
the  graduations. 

If  an  instrument  falls,  and  the  centers  become  bent,  it  should  be 
sent  at  once  to  the  maker  for  repairs,  as  every  turn  after  the  accident 
only  makes  the  condition  of  affairs  worse 

The  few  hints  here  given  it  is  hoped  will  be  of  service  to  users  of 
instruments,  and  familiarity  in  their  use  will  be  found  to  suggest  many 
other  things  which  the  man  possessed  of  common  sense  will  be  able  to 
adopt  and  find  of  service. 

An  instrument  is  a  finely  made  and  delicate  machine,  but  to  one 
who  thoroughly  understands  it,  the  limit  of  its  delicacy  can  be  under- 
stood, and  some  men  can  do  a  great  deal  more  to  one  in  the  way  of 
repairs  than  others.  The  old  maxim  of  ''every  man  to  his  trade"  is 
however  a  good  one  to  follow;  the  efforts  of  the  owner  should  be  con- 
fined to  the  keeping  of  his  instrument  clean  and  ready  for  service. 


LOOK  OUT  FOR  YOUR  NEEDLE. 


On  account  of  the  great  number  of  strong  electric  currents  over  the 
country,  the  magnetism  of  needles  is  more  apt  to  be  disturbed 
than  in  days  "  gone  by." 

Never  take  a  transit  into  an  electric  power  house. 

Keep  a  respectable  distance  away  from  dynamos  and  other  electric 
machinery  when  carrying  a  transit. 

Do  not  ride  on  electric  cars  when  carrying  a  transit,  if  possible  to 
avoid  it. 

If  compelled  to  ride  on  an  electric  car  with  a  transit,  let  the  needle 
swing  freely,  and  carry  the  instrument  on  your  lap.  Never  under 
any  circumstances  allow  the  transit  to  rest  on  the  floor  of  an 
electric  car. 

If  using  a  transit  near  strong  electric  currents  or  near  electrical 
machinery,  allow  the  needle  to  swing  freely. 

If  your  office  is  in  an  upper  story  of  a  high  office  building,  have  a 
piece  cf  thick  rubber  to  place  the  transit  box  on  and  always 
allow  the  needle  to  swing  freely. 


Surveyors'  and   Engineers' 
Instruments 


l-'OK 


Field    Work 


PART    A 


Ippp^-  jpBBlt 


THE    TRANSIT. 


J.    C.    SALA,    SAN    FRANCISCO 


THE    TRANSIT 


The  most  important  instrument  used  in  engineering  work  is  the 
transit,  and  its  invention  marked  a  great  advance  in  the  doing  of 
accurate  work.  It  can,  with  its  various  modifications,  do  the  work  of 
the  compass,  the  level,  and,  with  more  or  less  accuracy,  the  work  of 
the  chain  in  measuring  distances.  It  is  in  fact,  a  universal  instrument 
and  an  /Ymerican  invention.  Its  essential  parts  will  be  briefly 
explained. 

GRADUATIONS.  The  object  for  which  the  transit  was  invented 
was  to  obtain  closer  results  in  the  reading  of  angles  than  was  possible 
with  the  compass.  The  graduations  therefore,  by  which  close  reading 
is  obtained,  must  be  very  carefully  and  accurately  cut.  Those  cut  on 
automatic  dividing  machines  are  the  only  ones  to  be  depended  upon,  as 
every  line  is  uniform.  The  lines  must  be  clear  and  perfectly  straight; 
to  obtain  this,  only  silver  should  be  used,  as  it  is  of  uniform  density, 
and  there  is  no  danger  of  blowholes  or  defects  in  the  casting  such  as 
are  encountered  in  brass  or  other  materials  sometimes  used  for  the 
purpose  and  silver-plated  afterwards.  All  graduations  on  transits  made 
by  this  house  are  on  solid  silver. 

The  graduations  on  the  horizontal  plate  read  in  opposite  directions 
from  o  to  360  degrees  and  are  inclined  in  the  direction  of  the  reading. 

I  especially  invite  a  comparison  of  the  graduations  on  the  limbs 
and  verniers  made  by  my  automatic  dividing  engine  mentioned  under 
another  heading,  and  the  graduations  as  now  existing  on  a  good  many 
instruments  of  other  makes,  and  am  satisfied  that  the  practiced  eye 
of  the  connoisseur  will  at  once  observe  that  notwithstanding  the  extreme 
fineness  of  the  lines,  this  advantage  is  obtained  without  impairing  their 
distinctness. 

VERNIERS.  A  vernier  is  a  device  whereby  finer  readings  may  be 
obtained  than  by  any  other  method.  It  is  in  fact  an  auxiliary  scale 
and  is  so  made  that  a  certain  number  of  divisions  on  it  will  equal  one 
more  or  less  on  the  plate,  or  limb.  If  for  instance  a  plate  is  graduated 


26  ILLUSTRATED   CATALOGUE   OF 


into  degrees  and  quarters,  no  angle  can  be  read  which  is  less  than 
fifteen  minutes.  It  can  be  estimated  a  little  closer,  but  such  a  pro- 
ceeding is  only  refined  guesswork.  To  obtain  a  reading  say  to  half 
minutes,  a  vernier  must  be  used;  this  is  a  scale  so  divided  that  thirty 
divisions  on  it  will  equal  twenty -nine  on  the  plate.  Now  by  placing 
the  vernier  in  contact  with  the  plate  so  that  the  lines  on  each  end  are 
coincident  with  two  lines  on  the  plate,  it  may  be  seen  that  the  line  next 
to  the  end  is  not  exactly  coincident  with  any  line.  The  next  line  has 
an  increased  space  between  it  and  the  line  nearly  opposite  on  the  plate, 
and  that  this  difference  grows  uniformly  greater  until  it  gets  to  the 
middle  of  the  scale  when  the  middle  line  is  exactly  half  way  between 
two  lines  on  the  scale;  then  the  lines  begin  again  to  approach  until  the 
end  line  at  the  other  end  is  coincident  with  a  line  on  the  plate.  A  little 
reflection  will  show  that  each  graduation  on  the  vernier  is  one-thirtieth 
smaller  than  one  of  the  graduations  on  the  plate.  As  the  graduations 
on  the  plate  are  fifteen  minutes  each,  the  vernier  must  be  able  to  show 
a  difference  equal  to  one-thirtieth  of  fifteen  minutes,  or  thirty  seconds. 
Therefore,  to  find  how  closely  any  vernier  will  read,  it  is  only  necessary 
to  divide  the  value  of  a  division  on  the  plate  by  the  number  of  divisions 
on  the  vernier.  It  makes  no  difference  whether  the  graduations  on 
plate  and  vernier  are  straight  or  on  circles,  the  rule  holds  good;  the 
vernier  may  be  so  graduated  to  enable  a  finer  reading  of  the  foot  or  of 
degrees  or  any  other  unit. 

To  read  a  vernier  on  a  transit,  read  the  degrees  on  the  plate  and 
in  the  direction  indicated  by  the  numbering.  The  zero  of  the  vernier 
will  indicate  the  number  of  degrees,  and  if  it  coincides  with  one  of  the 
lines,  it  gives  the  exact  reading;  if  it  does  not  coincide  with  any  line, 
then  when  the  zero  point  is  reached  the  reading  must  be  on  the  vernier 
until  a  line  is  reached  which  coincides  with  a  line  on  the  plate.  The 
number  of  spaces  the  line  on  the  vernier  is  from  the  zero,  indicates  the 
number  of  units  of  the  ' '  smallest  reading  "  to  be  added  to  the  reading 
on  the  plate  as  indicated  by  the  zero  mark. 

The  graduations  on  the  horizontal  plate  of  the  transit  are  in  a 
circle,  and  the  vernier  is  on  a  small  plate  attached  to  a  circular  ring 
outside  the  graduated  plate.  To  obtain  close  readings,  the  line  divid- 
ing the  two  plates  should  be  very  fine  and  hardly  distinguishable;  it 


J.    C.    SAI,A,    SAN    FRANCISCO  27 


can  only  be  so  if  the  two  plates  are  in  precisely  the  same  plane.  If 
there  is  a  wide  space  between  the  graduated  plates  or  one  is  a  trifle 
higher  than  the  other,  the  transit  is  not  capable  of  doing  as  accurate 
work  as  is  necessary.  The  verniers  on  my  transits  are  placed  directly 
in  front  where  they  can  be  most  easily  read. 

THE  CENTERS.  The  centers  of  a  surveying  instrument  are  the 
fundamental  part  of  such  instrument.  Upon  the  axis  and  bearings 
depends  in  the  first  place  the  accuracy  of  measuring  either  horizon- 
tal or  vertical  angles,  and  also  on  their  trueness  depends  the  closeness 
of  the  line  between  the  horizontal  or  vertical  limb  and  its  vernier. 
Since  my  predecessor  started  in  business,  the  instruments  built  by  this 
firm  have  been  renowned  for  the  trueness  and  unsurpassed  wearing 
qualities  of  the  centers  of  their  instruments. 

The  fineness  of  the  line  between  the  vernier  and  the  plate  depends 
to  a  great  extent  upon  the  perfect  fitting  of  the  centers.  No  matter 
how  well  graduated  the  plates  or  how  excellent  the  workmanship  in 
other  parts  of  the  instrument,  if  the  centers  are  not  truly  fitted,  no 
good  work  can  be  done.  The  centers  support  all  the  vital  parts  of  the 
transit,  and  for  steadiness  should  be  long  and  fit  perfectly  at  all  points 
so  as  to  insure  firm  and  steady  bearings;  they  must  be  well  turned  in 
order  to  move  freely  without  binding  and  to  require  as  little  lubricating 
material  as  possible.  There  must  be  just  enough  lubricating  material 
on  the  centers  to  enable  the  surfaces  to  move  on  each  other  without 
grinding;  the  least  additional  amount  prevents  a  perfect  fit.  Any 
bending  of  the  centers  introduces  errors  and  sets  up  a  grinding  motion 
which  soon  renders  the  instrument  useless. 

The  centers  on  all  my  instruments  are  long  and  made  of  the  very 
hardest  bell  metal.  The  center  of  gravity  is  brought  down  as  low  as 
possible  and  steadiness  thus  insured. 

THE  PLATE  LKVELS.  To  obtain  correct  readings  of  horizontal 
angles,  the  instrument  must  be  level;  to  make  it  so,  there  are  two  level 
tubes  on  the  plate  at  right  angles  to  each  other.  One  is  parallel  to  the 
line  of  sight.  The  one  parallel  to  the  line  of  sight  is  sometimes  placed 
on  the  standards  supporting  the  telescope  and  the  other  on  the  plate. 

It  was  formerly  stated  that  it  did  not  matter  much  if  the  level  on 
the  side  was  a  little  out  of  adjustment,  as  the  angles  were  read  from 


28  ILLUSTRATED    CATALOGUE   OF 


an  imaginary  vertical  line  through  the  center  of  the  telescope  tube;  it 
was  thought  that  if  the  level  at  right  angles  was  perfectly  level,  angles 
could  be  correctly  read  even  if  the  other  level  was  out  slightly.  This 
idea  is  no  longer  entertained,  for  it  may  be  easily  perceived  that  if  the 
plate  is  not  truly  horizontal,  all  the  angles  will  be  too  small.  The 
repeated  clamping,  unclamping  and  turning  of  the  instrument  while 
making  observations,  has  a  tendency  to  throw  the  plate  slightly  out  of 
level,  and  it  is  therefore  necessary  that  the  plate  levels  should  be 
extremely  sensitive  in  order  that  the  least  amount  of  deviation  may  be 
ascertained  and  corrected  before  much  harm  is  done. 

All  levels  for  close  work  are  ground  to  a  true  arc  of  a  circle  and 
must  be  uniformly  ground  or  they  are  of  no  use.  A  very  good  idea 
can  be  formed  of  the  quality  of  work  put  in  an  instrument  by  noticing 
the  sensitiveness  of  the  levels;  unless  all  fittings  are  good,  the  levels 
will  always  be  unsteady  and  a  source  of  annoyance.  A  maker  puts  on 
his  instruments  as  sensitive  levels,  as  he  thinks  will  be  good  for  them 
to  have,  and  if  the  bubble  is  sluggish,  it  is  a  pretty  sure  indication  that 
the  workmanship  generally  is  not  first-class.  If  the  metal  in  the 
centers  is  soft,  a  sensitive  level  will  soon  tell  when  any  wearing  begins. 
To  insure  good  work  and  peace  of  mind  it  is  well  to  have  sensitive 
levels  on  an  instrument  and  the  value  of  the  graduations  known;  if 
the  level  gets  out  a  little  on  the  work,  the  operator  will  know  just  how 
much  his  work  is  likely  to  be  affected  and  can  govern  himself  accord- 
ingly. 

THE  LEVELING  SCREWS.  These  parts  of  an  instrument  are 
more  used  than  any  other,  and  therefore  require  to  be  made  of  hard 
metal,  and  the  threads  must  be  even  and  deep;  the  heads  should  be 
broad,  in  order  that  a  firm  hold  may  be  obtained  and  the  screws  turned 
easily.  The  leveling  arrangements  of  my  instruments  are  fully  in 
accord  with  the  best  modern  ideas.  The  parts  are  strong  and  the 
motion  easy  and  uniform. 

A  caution  to  be  remembered  in  using  an  instrument  is,  that  when 
a  screw  has  been  brought  to  a  firm  bearing^  all  turning  should  stop. 
An  extra  effort,  however  slight,  will  have  a  tendency  to  jam  the  screw 
and  interfere  with  easy  motion,  or  bend  a  thread,  and  thus  open  the 
way  for  future  trouble  and  expense. 


J.    C.    SALA,    SAN    FRANCISCO  2Q 

The  instruments  ordinarily  used  have  four  leveling  screws 
arranged  in  opposing  pairs.  To  level  the  plate,  one  pair  at  a  time  is 
turned,  each  screw  in  an  opposite  direction.  When  the  thumbs  move 
towards  each  other,  the  bubble  goes  towards  the  right;  when  they 
move  from  each  other,  the  bubble  goes  to  the  left.  Before  the  opera- 
tion is  commenced,  the  levels  must  be  parallel  with  the  pairs  of  screws. 

Four  screws  are  most  convenient  for  ordinary  instruments,  but 
transits  graduated  to  read  angles  of  io/x  or  less,  generally  have  only 
three  leveling  screws.  The  objections  to  three  screws  are  that  they 
make  necessary  a  little  increase  in  the  size  of  the  tripod  head,  and  con- 
sequently larger  tripod  legs  and  a  larger  carrying  case.  The  advan- 
tages of  three  leveling  screws  are  that  the  instrument  is  made  steadier, 
the  centers  are  relieved  of  some  strain  and  a  perfect  horizontal  adjust- 
ment is  obtained,  thus  insuring  a  high  degree  of  accuracy.  Instruments 
can  be  supplied  with  three  or  four  screws  as  desired. 

All  my  leveling  screws  are  capped  and  so  constructed  as  to  prevent 
dust  getting  on  the  threads.  The  transits  are  also  supplied  with  shift- 
ing centers,  which  permit  of  a  small  lateral  movement  of  the  upper 
part  of  the  transit  after  the  tripod  is  set,  and  thus  enables  an  accurate 
setting  over  a  point. 

TRIPOD  ATTACHMENT.  Several  devices  are  in  use  for  securing 
the  instrument  to  the  tripod,  but  none  are  so  satisfactory  as  the  screw. 
By  the  screw  the  fastening  is  secure,  and  timely  warning  is  given 
before  the  hold  loosens  to  an  extent  which  will  cause  a  severance  of  the 
parts.  The  only  real  objection  urged  against  the  screw,  is  the  time  it 
takes  to  attach  the  instrument  by  means  of  it;  this  objection  I  have 
overcome  by  providing  the  bottom  plate  with  a  double-threaded  screw. 
One  single  turn  and  a  half  will  fasten  the  instrument  firmly  in  place. 

THE  TELESCOPE.  We  now  come  to  a  part  of  the  transit  which 
is  of  not  much  less  importance  than  the  graduations.  The  telescope 
should  have  a  large  field  and  give  a  clear  definition;  it  should  be 
achromatic.  It  is  not  necessary  here  to  give  any  description  of  the 
principle  of  the  telescope,  as  all  good  works  on  optics  sufficiently  deal 
with  the  subject.  It  is  sufficient  to  state  that  my  telescopes  combine 
all  the  latest  improvements.  The  question  of  power  has  been  carefully 
considered,  and  with  forty-two  years'  experience  to  guide  me,  the 


30  ILLUSTRATED   CATALOGUE   OF 

telescopes  placed  on  my  transits  are  equal  to  all  demands  which  will 
ever  be  made  upon  them.  The  glasses  are  ground  to  special  formula, 
and  the  best  quality  of  glass  used.  The  telescope  tubes  are  castings, 
and  carefully  finished;  this  insures  rigidity  and  prevents  a  warping  of 
the  telescope.  This  is  the  invention  of  the  present  head  of  this  house, 
and  was  never  used  by  any  maker  before  my  instruments  were  thus 
fitted.  The  advantages  over  drawn  brass  tubes  are  apparent. 

The  axis  of  the  telescope  is  large,  and  of  hard  solid  bell  metal ; 
the  ends  are  corrugated  where  they  rest  in  the  uprights,  thus  giving  a 
large  bearing  with  steadiness  of  motion  and  securing  the  line  of  colli- 
mation.  The  telescope  is  so  placed  on  the  axis  that  it  is  perfectly 
balanced  when  the  sun  shade  is  on. 

The  object  end  is  furnished  with  a  slide  protector  which  prevents 
dust  and  grit  from  injuring  the  slide,  upon  which  the  perfection  of  the 
collimation  depends. 

The  eye  piece  is  provided  with  an  improved  screw  adjustment, 
permitting  the  cross  hairs  to  be  accurately  brought  into  focus  without 
shaking  or  jarring  the  instrument.  The  telescope  swings  freely  and  in 
a  full  circle.  The  eye  piece  is  erecting  but  can  be  made  inverting  if  so 
ordered.  An  erect  eye  piece  intercepts  more  light  than  an  inverting 
one,  but  is  convenient  to  use.  With  a  little  practice,  an  inverting  eye 
piece  offers  no  great  inconvenience,  and  for  stadia  work,  where  brilliancy 
of  the  object  observed  is  desirable,  it  is  to  be  recommended. 

STANDARDS.  The  standards,  or  uprights,  are  of  the  form  best 
calculated  to  do  the  work  required,  of  supporting  the  telescope  and  its 
various  attachments.  An  expanded  base  is  well  secured  to  the  upper 
plate  and  an  adjustment  is  provided  for  securing  the  revolution  of  the 
telescope  in  a  vertical  plane. 

COMPASS.  As  the  graduations  only  occupy  a  narrow  ring  on  the 
edge  of  the  plate,  there  is  a  vacant  space  inside  the  ring  and  between 
the  standards  which  is  utilized  by  placing  a  compass  box  therein.  The 
needle  is  as  long  in  all  cases  as  it  is  possible  to  put  in.  The  utility  of 
the  compass  as  a  portion  of  the  transit  is  too  apparent  to  require  any 
special  remarks.  The  compasses  on  my  transits  are  as  carefully  made 
as  any  other  part  of  the  instrument,  and  especial  care  is  taken  that  the 


J.    C.    SAIvA,    SAN   FRANCISCO  31 


graduations  will  coincide  exactly  with  the  graduations  on  the  horizontal 
limb;  this,  if  not  done,  sometimes  causes  wide  differences  in  bearings 
of  lines  when  observed  with  different  instruments.  The  line  of  colli- 
mation  of  the  telescope  must  exactly  coincide  with  the  north  and  south 
line  engraved  on  the  compass  ring,  and  the  line  through  the  o°  and 
1 80°  graduations  on  the  horizontal  limb. 

As  to  what  is  embodied  in  a  good  compass,  see  chapter  on 
compasses. 

CLAMP  AND  TANGENT  SCREWS.  The  clamp  and  tangent  screws 
are  of  German  silver  or  aluminum  alloys,  either  metal  being  used  where 
it  is  deemed  best.  For  clamping  the  whole  instrument,  the  tangent 
screws  are  either  of  the  improved  spring  pattern  or  have  two  opposing 
screws  of  the  old  pattern.  While  this  latter  form  requires  the  use  01 
both  hands  in  setting  the  sight,  it  has  the  advantage  of  being  firmly 
set  and  requiring  no  further  attention.  With  an  opposing  spring,  the 
screw  works  as  it  were,  against  a  cushion,  and  is  liable  to  derangement 
if  the  instrument  is  standing  for  any  length  of  time  over  one  point  as 
frequently  happens.  The  upper  tangent  screw  controlling  the  move- 
ment of  the  plates,  is  of  the  improved  spring  pattern,  as  it  is  placed 
where  it  is  under  easy  control  and  is  convenient  to  use,  requiring  only 
one  hand.  The  heads  of  all  screws  are  broad  and  easy  to  grasp  and 
turn. 

TRIPOD.  The  tripod  legs  are  made  round,  but  split  leg  tripods 
are  furnished  when  ordered;  the  upper  ends  of  the  legs  are  pressed 
firmly  on  each  side  of  a  strong  tenon  on  the  solid  bronze  head  by  a 
bolt  and  thumb  screw  on  opposite  sides  of  the  leg.  To  set  the  tripod 
up  easily,  the  legs  should  move  freely  but  not  loosely  on  this  tenon; 
when  they  become  loose  they  may  be  tightened  by  means  of  the  thumb 
screw-  this  obviates  the  necessity  for  carrying  a  screw  driver  or  wrench 
for  the  purpose.  A  strap  with  buckle  is  fastened  to  one  of  the  legs 
near  the  lower  end  for  the  purpose  of  fastening  the  legs  together  for 
shipment.  The  lower  end  of  the  leg  has  a  brass  shoe  with  iron  point, 
securely  fastened  and  riveted  to  the  wood. 

Extension  tripods  can  be  furnished  if  desired;  they  are  conven- 
ient when  using  the  transit  in  confined  spaces,  as  on  very  steep  hillsides. 


32  ILLUSTRATED    CATALOGUE   OF 


ATTACHMENTS   OF   THE   TRANSIT. 


The  foregoing  description  is  of  what  is  known  as  the  plain  transit 
with  it,  lines  can  be  ranged  and  angles  turned  to  right  or  left  of  th< 
lines.  To  increase  its  range  of  usefulness,  there  are  certain  attach 
ments  which  are  termed  "extras."  The  first  generally  added,  is  5 
level  tube  beneath  the  telescope  and  a  clamp  and  tangent  screw  on  th< 
standards  to  control  it;  by  adding  this  level  tube,  the  transit  can  thei 
be  used  for  leveling.  A  vertical  circle,  or  arc,  added  to  the  telescop< 
axis  with  a  vernier  on  the  standard,  makes  it  possible  to  take  vertica 
angles.  Two  extra  hairs  (called  stadia  hairs)  placed  inside  the  telescop< 
enable  distances  to  be  measured  by  rod  readings.  A  graduated  heac 
placed  on  the  tangent  screw  of  the  telescope  makes  what  is  termed  i 
gradienter;  by  its  means,  grades  can  be  established,  and  horizonta 
distances^  vertical  angles  and  differences  of  level  can  be  measured  witl 
great  rapidity. 

THE  GRADIENTER.  The  head  of  the  screw  on  the  clamp  for  the 
telescope  is  divided  into  one  hundred  equal  parts;  over  it  is  a  scale 
which  is  divided  into  spaces,  each  of  which  is  equal  to  one  revolutior 
of  the  screw,  so  that  by  comparing  the  edge  of  the  head  with  the  scale 
the  number  of  revolutions  made  can  be  ascertained.  If  the  telescope  i* 
clamped  and  the  screw  turned,  it  will  be  seen  that  the  end  of  th« 
telescope  will  be  moved  vertically,  and  as  one  complete  revolution  o: 
the  screw  will  move  the  horizontal  cross  wire  over  a  space  of  one  fool 
on  the  rod  held  at  a  distance  of  one  hundred  feet,  it  may  be  easily  seer 
that  distances  can  be  read  by  means  of  the  gradienter  with  the  same 
facility  as  with  the  stadia. 

Grades  can  be  established  as  follows:  First  level  the  instrumenl 
and  then  bring  the  bubble  under  the  telescope  to  the  center  of  the  tube, 
move  the  gradienter  screw  until  the  zero  is  opposite  the  zero  on  the 
scale,  and  clamp  the  telescope;  then  turn  off  as  many  spaces  on  the 
head  as  there  are  hundredths  of  feet  to  the  hundred  in  the  grade  to  be 


J.    C.    SALA,    SAN    FRANCISCO  33 


established.     Sometimes  there  are  fewer  graduations  on  the  screw  than 
stated  above,  but  the  principle  and  method  are  the  same. 

For  setting  off  the  variation  of  the  needle,  an  adjustable  arc  is 
often  placed  inside  the  compass  box.  In  my  transits,  the  variation  arc 
is  placed  outside  the  compass  ring,  thus  obtaining  a  large  radius,  and 
being  graduated  to  minutes,  the  engineer  is  enabled  to  read  and  set 
the  variation  with  ease. 

SAEGMULLER  SOLAR  ATTACHMENT.  As  the  transit  is  sometimes 
used  to  retrace  lines  which  have  been  previously  run  with  a  needle,  or 
to  run  lines  the  bearing  of  which  it  is  necessary  to  correct  by  observations 
on  the  sun  in  order  to  obtain  the  true  bearing,  there  have  been  various 
forms  of  solar  attachments  invented.  The  best  known  and  most  widely 
used  are  the  Burt  and  the  Saegmuller;  I  keep  both  makes  and  put  them 
on  any  transit  to  order.  Directions  for  their  use  are  given  in  all  standard 

works  on  survey- 
ing, and  the  makers 
get  out  special  direc- 
tions for  use,  with 
tables,  etc.  The 
Saegmuller  has  the 
advantage  over  the 
Burt  of  having  a 
telescope,  and  a 
transit  fitted  with  it 
can  be  used  for 
sighting  down 
shafts  like  a  mining 
SAEGMULLER  SOLAR  ATTACHMENT.  transit. 

The  transit  can  be  provided  with  open  sights  attached  to  the 
standards  to  make  offsets  at  right  angles  to  the  line  of  collimation  of 
the  telescope,  if  such  sights  are  desired. 

A  transit  with  all  the  attachments  mentioned,  is  called  a  complete 
transit. 

All  transits  are  furnished  with  a  carrying  case  supplied  with  a 
leather  strap,  rubber  supports,  good  lock  and  hooks,  and  contains 
plumb  bob,  sun  shade,  adjusting  pins  and  magnifying  glass. 


34 


ILLUSTRATED   CATALOGUE   OF 


TRANSIT  No.  1-PRICE  $185. 


J.    C.    SALA,    SAN    FRANCISCO 


35 


TRANSIT    No.   I. 


The  engineers'  plain  transit  as  manufactured  by  J.  C.  Sala,  has 
.11  1 1 -inch  telescope,  which  is  provided  with  achromatic  lenses  of  high 
•ower,  slide  protector,  sun  and  dust  shades.  The  telescope  reverses  at 
>oth  ends.  The  object  glass  of  the  telescope  has  an  aperture  of  i^ 
tiches;  its  eye  piece  is  provided  with  a  screw  adjustment.  The  axis 
>f  the  telescope  is  large  and  of  .solid  hard  bell  metal.  The  horizontal 
date  is  of  seven  inches  diameter,  with  double  verniers  graduated  on 
olid  silver,  reading  to  thirty  seconds.  The  circle  of  the  compass  box 
5  graduated  to  thirty  minutes,  the  needle  is  43/6  inches  long,  with  agate 
•earing;  the  compass  box  has  on  its  outside,  a  variation  plate  with 
•ernier  reading  to  single  minutes. 

The  small  graduated  bubbles  of  the  levels  on  the  horizontal  plate 
re  ground  and  graduated  to  the  greatest  accuracy;  the  tangent  screw 
f  the  horizontal  plate  is  provided  with  a  compensating  spring;  the 
angent  screw  to  the  center  of  the  instrument  is  also  provided  with  a 
ompensating  spring.  The  leveling  screws  are  protected  with  a  dust 
nd  grit  cap  covering  the  whole  of  the  thread  of  these  screws;  they 
est  upon  a  shifting  plate  which  moves  upon  the  bottom  plate  screwed 
o  the  tripod;  this  allows  the  instrument  to  be  shifted  accurately  over 
.ny  given  point,  and  when  the  leveling  screws  are  set,  the  shifting 
•late  becomes  fixed.  The  center  upon  which  most  of  the  efficacy  and 
.ccuracy  of  the  instrument  depends,  has  a  bearing  length  of  4^  inches. 

The  tripod  is  made  with  either  split,  solid  or  extension  legs,  as 
lesired.  The  case  is  furnished  with  a  leather  strap,  rubber  supports, 
^ood  lock  and  hooks,  and  contains  plumb  bob,  sun  shade,  adjusting 
>ins  and  magnifying  glass. 


ILLUSTRATED   CATALOGUE   OF 


ENGINEERS'  TRANSIT,   No.   2-PRICE    $210. 


The  description  of  this  instrument  is  the  same  in  size  and  partic- 
ulars as  No.  i ,  with  the  addition  of  clamp  and  tangent  attachment  tc 
axis,  and  level  to  telescope,  with  a  finely  ground  and  graduated  bubble 


J.    C.    SALA,    SAN   FRANCISCO 


37 


ENGINEERS'  COMPLETE  TRANSIT,  No.  3— PRICE  $235. 


This  instrument  is  the  same  in  size  and  particulars  as  No.  i ,  with 
le  addition  of  clamp  and  tangent  attachment  to  axis  and  level  to 
ilescope,  with  a  finely  ground  and  granulated  bubble;  vertical  arc  with 
ernier  reading  to  thirty  seconds;  (all  graduations  on  solid  silver)  this 
istrument  is  the  most  desirable,  having  all  the  necessary  attachments  for 
sneral  work,  being  of  good  size,  strong  and  yet  not  too  heavy  to  carry. 


ILLUSTRATED    CATALOGUE   OF 


SURVEYORS'  TRANSIT,    No.   4-PRICE    $250- 


Has  a  horizontal  plate  8  inches  in  diameter,  with  two  verniers 
reading  to  thirty  seconds.  Length  of  needle  5  inches.  Clamp  and 
tangent  attachment  to  axis  and  level  to  telescope,  with  a  finely  ground 
and  graduated  bubble;  vertical  circle,  5  inches  in  diameter,  and  vernier 
reading  thirty  seconds.  For  other  particulars,  see  description  of  No.  i. 


J.    C.    SALA,    SAN    FRANCISCO 


COMBINED    MINING,    MOUNTAIN    AND 
SOLAR    TRANSIT. 


I  manufacture  a  combined  mining  and  mountain  transit  with  two 
telescopes  parallel  to  each  other;  the  upper  one,  although  detachable, 
is  securely  fastened  to  the  one  revolving  in  the  standards,  by  supports 
and  thumb  screws.  The  telescopes  are  supplied  with  achromatic  lenses 
of  twenty  magnifying  power,  rack  movement  for  the  object  glass,  fixed 
or  adj  ustable  stadia  hairs,  movable  prism  to  fit  the  eye  pieces  of  either 
telescope.  To  the  telescope  revolving  in  the  standards  is  attached  an 
hour  arc  and  center  column  for  a  solar  attachment,  and  under  it  a  level 
of  precision ;  the  divisions  of  its  bubble  reading  to  ten  seconds  of  arc. 
Both  telescopes  are  provided  with  a  slide  protector  and  a  sun  shade, 
also  with  a  silver  reflector  for  illuminating  cross  hairs  in  mining  or 
night  work.  The  vertical  circle  attached  to  the  axis  of  the  telescope 
and  its  vernier  are  graduated  on  solid  silver,  and  read  to  either  thirty 
seconds  or  one  minute,  as  desired. 

The  micrometer  tangent  screw  with  compensating  spring  on  the 
upright,  is  provided  with  a  gradienter  attachment.  The  standards  are 
also  furnished  with  open  sights  giving  a  line  of  90°  to  the  line  of  colli- 
mation  of  the  telescopes.  The  circle  of  the  compass  box  is  graduated 
to  thirty  minutes,  the  needle  being  3^  inches  long,  with  agate  bearing. 
The  compass  box  has  on  its  outside,  a  variation  plate  with  vernier 
reading  to  minutes. 

The  small  graduated  bubbles  of  the  levels  on  the  horizontal  plate 
are  ground  and  graduated  to  the  greatest  accuracy.  The  horizontal 
limb  and  verniers  are  graduated  on  solid  silver,  and  read  directly  under 
the  eye  piece  and  object  glass  of  the  telescope  to  thirty  seconds  on  a 
beveled  surface  at  an  angle  of  30°.  The  tangent  screw  is  provided  with 
a  compensating  spring. 

The  leveling  screws  are  protected  by  caps  and  rest  upon  a  shifting 
plate  which  moves  upon  the  bottom  plate  screwed  to  the  tripod;  this 
allows  the  instrument  to  be  shifted  accurately  over  any  given  point, 
and  when  the  leveling  screws  are  set,  the  shifting  plate  becomes  fixed. 
The  center,  upon  which  most  of  the  efficiency  of  the  instrument 
depends,  has  a  bearing  length  of  four  inches.  The  tripod  is  made  with 
either  split,  solid  or  extension  legs,  as  desired. 


H.l.rSTRATKl)    CATAIX)GUE 


COMBINED    MINING,    MOUNTAIN    AND    SOLAR    TRANSIT,    No.   5, 

WITH  DOUBLE  TELESCOPE  TO  TAKE  VERTICAL 

ANGLES— PRICE  $335. 


J.    C.    SALA,    SAN    FRANCISCO 


COMBINED   MINING,  MOUNTAIN  AND  SOLAR  TRANSIT,  No.  5— 
SHOWING  SOLAR  ATTACHMENT, 


ILLUSTRATED   CATALOGUE   OF 


LIGHT    MOUNTAIN    TRANSIT,   No.   6-PRICE    $220. 


Having  a  horizontal  plate  6  inches  in  diameter,  with  double  v< 
niers  reading  thirty  seconds;  improved  spring  tangent  screws,  magne 
needle  3^  inches  long,  with  adjustable  variation  arc,  4-inch  vcrtii 
circle.  A  telescope  8  inches  in  length,  with  high  magnifying  pow< 
aperture  of  object  glass  i  inch;  erect  eye-piece,  and  reversing  at  bo 
ends.  To  the  tangent  screw  of  the  vertical  arc  is  attached  a  gradie 
ter,  and  by  its  means,  grades,  horizontal  distances,  vertical  angles  a: 
differences  of  level  can  be  obtained. 


J.    C.    SAI.A,    SAN   FRANCISCO 


43 


COMBINED    MINING    AND    SOLAR    TRANSIT,   No.   7— PRICE,  $290. 

This  instrument  is  the  same  as  No.  4,  only  differing  from  it  in  having  the 
Saegmuller  attachment;  this  answers  all  the  purposes  of  a  side  telescope  in  taking 
perpendicular  sights  in  mining  work.  The  Saegmuller  Solar  Attachment  to  this 
instrument  enables  the  engineer  to  establish  accurately  the  astronomical  meridian 
The  advantages  of  this  solar  attachment  are:— It  is  more  accurate,  it  is  simpler 
and  easier  of  adjustment,  it  can  be  used  when  the  sun  is  partly  ocscured  by  the 
clouds,  it  can  be  used  where  the  sun  is  quite  close  to  the  meridian,  the  time  can 
be  obtained  with  it  reliable  to  within  a  few  seconds  with  perfect  ease,  and  as 
stated  above,  it  can  be  used  as  a  vertical  telescope  in  mining  surveying. 


ILLUSTRATED    CATALOGUE   OF 


HOW   TO   ADJUST   THE   TRANSIT. 


Every  transit  should  be  properly  adjusted  by  the  maker  befor 
leaving  his  hands,  they  are  however  liable  to  derangement  by  transpor 
tation,  and  a  few  remarks  on  the  adjustments  will  not  prove  useless 
These  are  the  levels,  the  standards,  the  line  of  collimation,  the  vertica 
circle  and  the  level  to  telescope. 

To  ADJUST  THE  LEVELS.  Set  the  instrument  upon  its  tripoi 
as  nearly  level  as  possible,  unclamp  the  plates  and  bring  the  levels  ii 
line  with  the  leveling  screws,  and  by  these  bring  the  bubbles  betweei 
the  lines,  and  when  both  are  in  place,  turn  the  instrument  half-wa; 
around;  if  the  bubbles  stay  in  the  center,  they  will  need  no  correction 
but  if  not,  turn  the  small  screw  at  the  ends  of  the  levels  with  tb 
adjusting  pin  until  the  bubbles  are  moved  half  the  error,  then  bring  tli 
bubbles  in  center  by  the  leveling  screws,  and  repeat  the  operation  unti 
the  bubbles  remain  in  the  center,  and  the  adjustment  will  be  complete 

Care  should  be  taken  to  loosen  one  end  of  the  level  screw  befor 
tightening  the  other,  so  as  to  not  strain  the  tube. 

To  ADJUST  THE  STANDARDS.  Set  up  the  instrument  in  a  plao 
where  a  very  steep  point  can  be  obtained,  giving  a  long  vertical  line 
Carefully  level  the  instrument  and  bring  the  wires  on  some  high  object 
clamp  the  plates,  then  bring  the  telescope  down  until  the  wires  striki 
some  well  defined  point  at  the  base,  turn  the  instrument  half  round,  fh 
the  wires  on  the  same  high  point,  clamp  the  plates  and  bring  th< 
telescope  down;  if  the  wires  strike  the  same  point  as  before,  the  vertica 
adjustment  is  correct,  if  not,  by  means  of  the  adjusting  screw,  place( 
in  one  of  the  standards,  raise  or  lower  the  adjusted  piece  half  th< 
difference  found,  and  repeat  until  the  adjustment  is  correct. 

To  ADJUST  THE  LINE  OF  COLLIMATION.  Set  the  instrumen 
firmly  on  the  ground  and  level  it  carefully,  and  then  having  brough 
the  wires  into  the  focus  of  the  eye  piece,  adjust  the  object  glass  01 
some  well  defined  point,  as  the  edge  ot  a  chimney  or  other  object,  at  i 
distance  of  from  200  to  500  feet;  determine  if  the  vertical  wire  i: 
plumb,  by  clamping  the  instrument  firmly  and  applying  the  wire  to  th( 


J.    C.    SALA,    SAN    FRANCISCO  45 


•ertical  edge  of  a  building,  or  observing  if  it  will  move  parallel  to  a 
point  taken  a  little  to  one  side;  should  any  deviation  be  manifested, 
loosen  the  cross-wire  screws,  and  by  Hie  pressure  of  the  hand  on  the 
head  outside  the  tube,  move  the  ring  around  until  the  error  is  corrected. 
The  wires  being  thus  made  respectively  horizontal  and  vertical,  fix 
their  point  of  intersection  on  the  object  selected;  clamp  the  instrument 
to  the  spindle,  and  having  revolved  the  telescope,  find  or  place  some 
•rood  object  in  the  opposite  direction,  and  at  about  the  same  distance 
from  the  instrument  as  the  first  object  assumed. 

Great  care  should  always  be  taken  in  turning  the  telescope,  that 
the  position  of  the  instrument  upon  the  spindle  is  not  in  the  slightest 
degree  disturbed. 

Now,  having  found  or  placed  an  object  which  the  vertical  wire 
bisects,  unclamp  the  instrument,  turn  it  half  way  around  and  direct  the 
telescope  to  the  first  object  selected;  having  bisected  this  with  the  wires, 
again  clamp  the  instrument,  revolve  the  telescope,  and  note  if  the 
vertical  wire  bisects  the  second  object  observed.  Should  this  happen, 
it  will  indicate  that  the  wires  are  in  adjustment,  and  the  points  bisected 
are  with  that  of  the  center  of  the  instrument,  in  the  same  straight  line; 
if  not,  then  move  one-quarter  of  the  difference,  using  the  two  capstan 
head  screws  on  the  sides  of  the  telescope,  these  being  the  ones  which 
affect  the  position  of  the  vertical  wire,  and  repeat  until  the  line  of 
collimation  is  adjusted. 

Remember  that  the  eye  piece  inverts  the  position  of  the  wires, 
and  therefore  that  in  loosening  one  of  the  screws  and  tightening  the 
other  on  the  opposite  side,  the  operator  must  proceed  as  if  to  increase 
the  error  observed. 

To  ADJUST  THE  VERTICAL  CIRCLE.  Having  the  instrument 
firmly  set  up  and  carefully  leveled,  bring  into  line  the  zeros  of  the 
circle  and  vernier,  and  with  the  telescope  find  or  place  some  well 
defined  point  or  line,  from  100  to  500  feet  distant,  which  is  cut  by  the 
horizontal  wire.  Turn  the  instrument  half  way  around,  revolve  the 
telescope,  and  fixing  the  wire  upon  the  same  point  as  before,  note  if 
the  zeros  are  again  in  line;  if  not,  loosen  the  capstan  head  screws, 
which  fasten  the  vernier,  and  move  the  zero  of  the  vernier  over  half 
the  error;  bring  the  zeros  again  into  coincidence,  and  proceed  precisely 


46  ILLUSTRATED   CATALOGUE   OF 

as  at  first,  until  the  error  is  entirely  corrected,  when  the  adjustment  will 
be  complete.  A  slight  error  may  be  most  readily  removed  by  putting 
the  zeros  in  line  and  then  moving  the  wire  itself  over  half  the  interval. 

The  level  is  adjusted  by  bringing  the  bubble  carefully  into  the 
center  by  the  nuts  at  each  end,  and  when  there  is  a  vertical  circle  on 
the  instrument,  this  should  be  done  when  the  zeros  of  the  circle  and 
vernier  are  in  line  and  in  adjustment. 

To  ADJUST  THE  lyEVEL  ON  TELESCOPE.  First  level  the  instru- 
ment carefully,  and  with  the  clamp  and  tangent  movement  to  the  axis, 
make  the  telescope  horizontal,  as  near  as  may  be,  with  the  eye;  then, 
having  the  line  of  collimation  previously  adjusted,  drive  a  stake  at  a 
convenient  distance,  say  from  100  to  300  feet,  and  note  the  height  cut 
by  the  horizontal  wire  upon  a  staff  set  on  the  top  of  the  stake.  Fix 
another  stake  in  the  opposite  direction,  and  at  the  same  distance  from 
the  instrument,  and  without  disturbing  the  telescope,  turn  the  instru- 
ment upon  its  spindle,  set  the  staff  upon  the  stake  and  drive  in  the 
ground  until  the  same  height  is  indicated  as  in  the  first  observation; 
the  top  of  the  two  stakes  will  then  be  in  the  same  horizontal  line, 
however  much  the  telescope  may  be  out  of  level.  Now  remove  the 
instrument  from  fifty  to  one  hundred  feet  to  one  side  of  either  stakes, 
and  in  line  with  both;  again  level  the  instrument,  clamp  the  telescope 
as  nearly  horizontal  as  may  be,  and  note  the  heights  indicated  upon  the 
staff  placed  first  upon  the  nearest  and  then  upon  the  most  distant 
stake.  If  both  agree,  the  telescope  is  level;  if  they  do  not  agree,  then 
with  the  tangent  screw  move  the  wire  over  nearly  the  whole  error,  as 
shown  at  the  distant  stake,  and  repeat  the  observation  as  described. 
Proceed  thus  until  the  horizontal  wire  will  indicate  the  same  height  at 
both  stakes,  when  the  telescope  will  be  truly  horizontal.  Taking  care 
not  to  disturb  its  position,  bring  the  bubble  into  the  center  by  the  little 
leveling  nuts  at  the  end  of  the  tube,  when  the'  adjustment  will  be 
completed. 


J.    C.    SAI,A,    SAN   FRANCISCO 


47 


THE     LEVEL. 


The  level  is  an  instrument  of  precision  for  ascertaining  the  differ- 
ence in  elevation  between  points.  There  are  two  different  forms  in 
general  use.  The  Dumpy  level  is  of  simple  construction  and  excellent 
for  working;  it  retains  its  adjustments  much  longer  than  a  Y  level,  but 
once  out,  the  adjustments  are  not  so  easily  made  as  in  the  latter,  and 
for  this  reason  many  prefer  the  Y  level.  Both  forms  are  made  by  this 
house. 

The  remarks  about  the  telescope,  centers,  leveling  .screws,  clamp 
and  tangent  screws,  level  tubes,  tripods,  and  general  workmanship  in 
the  chapter  011  the  transit,  apply  also  to  our  levels.  The  workmanship 
is  the  best  and  the  latest  improvements  are  adopted. 


48  ILLUSTRATED    CATALOGUE   OF 


ENGINEERS'   Y    LEVEL,    No.   8 

PRICE  $150. 

The  telescope  is  21  inches  long,  has  a  power  of  50  diameters, 
aperture  of  object  glass  i^  inches,  clear;  erect  eye  piece,  achromatic 
perfect,  defines  sharply,  has  a  flat  field  with  great  penetrating  power, 
which  is  essential  in  good  leveling.  The  eye  piece  is  provided  with  a 
semi-circular  movement,  very  convenient  for  focussing  the  cross  wires 
without  shaking  the  instrument.  The  telescope  has  two  extra  wires 
for  stadia  measurements.  The  collars  are  of  the  hardest  metal,  with 
clamp  .screws  to  keep  the  cross  wires  in  horizontal  position.  The  spirit 
level  is  8^  inches  long;  the  bubble  is  very  sensitive  and  finely  grad- 
uated. The  object  end  is  provided  with  a  slide  protector,  which  pre- 
vents dirt  or  dust  from  injuring  the  slide  upon  which  perfect  adjustment 
depends.  The  center  is  3^  inches  long,  stout  and  of  the  hardest  bell 
metal  or  steel.  The  four  large  leveling  screws  are  perfectly  covered. 
It  has  an  improved  spring  tangent  screw  and  a  clamp  to  the  center. 
The  bar  is  13  inches  long,  very  heavy,  and  it  is  attached  to  the  tripod 
in  the  same  manner  as  transit  No.  i. 

The  case  is  furnished  with  heavy  leather  straps,  rubber  supports, 
good  lock,  adjusting  pins  and  sun  shade. 


ENGINEERS'   Y    LEVEL,    No.    9 

PRICE    $140. 

Telescope  19  inches,  (description  same  as  No.  8)  bar  n  inches 
long,  heavy;  length  of  spirit  level  7^  inches.  Center  and  leveling 
screws  (as  described  in  No.  8). 


ENGINEERS'   Y    LEVEL,    No.    10 

PRICE    $130. 

Telescope  17  inches  long,  aperture  of  object  glass  i^  inch,  (for 
description  see  No.  8)  bar  10  inches  long,  spirit  level  6]/2  inches,  with 
a  fine  graduated  bubble.  Center  and  leveling  screws  (as  described  in 
No.  8).  This  instrument  is  the  most  convenient  size  for  general  work. 


J.    C.    SALA,    SAN   FRANCISCO 


49 


DUMPY    LEVEL,   No.   11— PRICE   $90. 

This  level  is  expressly  designed  for  irrigation,  having  an  erecting 
telescope  16  inches  long,  with  a  magnifying  power  of  thirty  diameters, 
and  a  large  sensitive  bubble,  with  the  level  tube  enclosed  in  a  revolving 
protecting  tube,  thus  allowing  the  bubble  to  be  perfectly  covered  when 
not  in  use. 

This  level  has  been  approved  by  competent  irrigation  engineers, 
as  being  the  most  suitable  for  their  use. 


No.   12— Architects'  or  builders'  level,  with  a  telescope  12  inches 
long,  erect  eye  piece,  ground  graduated  bubbles.     Price  $60. 


No.   13— Farmers'  or  drainage  levels  of  all  description,  from  $15 
to  $40. 


50  ILLUSTRATED    CATALOGUE   OF 


HYDROGRAPHIC    Y    LEVEL. 

On  special  order  I  make  a  superior  Y  level  with  three  leveling 
screws  in  place  of  four,  and  a  reflecting  mirror  to  enable  a  quick  and 
accurate  setting  of  the  bubble  without  rendering  necessary  a  change 
of  position  by  the  observer.  Price  upon  application. 


REVERSION    LEVELS. 

Sometimes  the  wyes  in  which  the  level  telescope  rest  or  the  collars 
of  the  telescope  wear  unequally,  and  the  bubble  underneath  the  teles- 
cope if  desired  can  be  so  ground  that  the  telescope  can  be  revolved  in 
its  collars  and  the  bubble  thus  brought  on  the  upper  side,  and  indicate 
in  that  position  also  a  level  line  (thus  correct  levels  can  be  taken  when 
the  collars  are  badly  worn).  While  this  is  an  ingenious  idea,  it  is 
based  upon  the  same  principle  as  the  repeating  of  angles  in  transit 
work.  If  the  engineer  desires  to  go  to  all  the  trouble  necessary,  he 
can  do  as  good  work  with  his  instrument  supplied  with  an  ordinary 
bubble. 

I  grind  bubbles  for  reversion  levels  to  order. 


HOW    TO    ADJUST    THE    LEVEL. 

To  ADJUST  THE  LEVEL  BUBBLE.  Clamp  the  instrument  over 
either  pair  of  leveling  screws  and  bring  the  bubble  into  the  center  of 
the  tube;  now  turn  the  telescope  in  the  wyes,  so  as  to  bring  the  level 
tube  on  either  side  of  the  center  of  the  bar.  Should  the  bubble  run  to 
the  end,  it  would  show  that  the  vertical  plane,  passing  through  the 
center  of  the  bubble,  was  not  parallel  to  that  drawn  through  the  axis 


J.    C.    SALA,    SAN   FRANCISCO  51 


of  the  telescope  rings.  To  correct  the  error,  bring  the  bubble  entirely 
back,  with  the  capstan  head  screws,  which  are  set  in  either  side  of  the 
level  holder,  placed  usually  at  the  object  end  of  the  tube.  Again  bring 
the  level  tube  over  the  center  of  the  bar,  and  the  bubble  to  the  center; 
turn  the  level  to  either  side,  and  if  necessary,  repeat  the  correction 
until  the  bubble  will  keep  its  position,  when  the  tube  is  turned  half  an 
inch  or  more  to  either  side  of  the  center  of  the  bar.  The  necessity  of 
this  operation  arises  from  the  fact  that  when  the  telescope  is  reversed 
end  for  end  in  the  wyes,  in  the  other  and  principal  adjustment  of  the 
bubble,  we  are  not  certain  of  placing  the  level  tube  in  the  same  vertical 
plane,  and  therefore  it  would  be  almost  impossible  to  effect  the  adjust- 
ment without  a  lateral  correction. 

Having  now,  in  a  great  measure,  removed  the  preparatory  diffi- 
culties, we  proceed  to  make  the  level  tube  parallel  with  the  bearings  of 
the  Y  rings.  To  do  this,  bring  the  bubble  into  the  center  with  the 
leveling  screws,  and  then,  without  jarring  the  instrument,  take  the 
telescope  out  of  the  wyes  and  reverse  it  end  for  end.  Should  the  bubble 
run  to  either  end,  lower  that  end,  or  what  is  equivalent,  raise  the  other 
by  turning  the  small  adjusting  nuts  on  one  end  of  the  level,  until  by 
estimation  half  the  correction  is  made;  again  bring  the  bubble  into  the 
center  and  repeat  the  whole  operation,  until  the  reversion  can  be  made 
without  causing  any  change  in  the  bubble.  It  would  be  well  to  test 
the  lateral  adjustment,  and  make  such  correction  as  may  be  necessary 
in  that,  before  the  horizontal  adjustment  is  entirely  completed. 

To  ADJUST  THE  WYES.  Having  effected  the  previous  adjust- 
ments, it  remains  now  to  describe  that  of  the  wyes,  or,  more  precisely, 
that  which  brings  the  level  into  position  at  right  angles  to  the  vertical 
axis,  so  that  the  bubble  will  remain  in  the  center  during  an  entire 
revolution  of  the  instrument.  To  do  this,  bring  the  level  tube  directly 
over  the  center  of  the  bar  and  clamp  the  telescope  firmly  in  the  wyes, 
placing  it  as  before,  over  two  of  the  leveling  screws,  unclamp  the 
socket,  level  the  bubble,  and  turn  the  instrument  half  way  round,  so 
that  the  level  bar  may  occupy  the  same  position  with  respect  to  the 
leveling  screws  beneath.  Should  the  bubble  run  to  either  end,  bring  it 
halfway  back  by  the  Y  nuts  on  either  end  of  the  bar;  now  move  the 
telescope  over  the  other  set  of  leveling  screws,  bring  the  bubble  again 


52  ILLUSTRATKD    CATALOGUE    OF 


into  the  center  and  proceed  precisely  as  previously  described,  changing 
to  each  pair  of  screws,  successively,  until  the  adjustment  is  very  nearly 
perfected,  when  it  may  be  completed  over  a  single  pair.  The  object  of 
this  approximate  adjustment,  is  to  bring  the  upper  parallel  plate  of  the 
tripod  head  into  a  position  as  nearly  horizontal  as  possible,  in  order 
that  no  essential  error  may  arise,  in  case  the  level,  when  reversed,  is 
not  brought  to  its  former  situation.  When  the  level  has  been  thus 
completely  adjusted ,  if  the  instrument  is  properly  made  and  the  sockets 
well  fitted  to  each  other,  and  the  tripod  head,  the  bubble  will  reverse 
over  each  pair  of  screws  in  any  position. 

To  ADJUST  THE  LINE  OF  COLLIMATION.  Set  the  tripod  firmly, 
remove  the  Y  pins  from  the  clips,  so  as  to  allow  the  telescope  to  turn 
freely;  clamp  the  instrument  to  the  tripod  head,  and  by  the  leveling 
and  tangent  screws  bring  either  of  the  wires  upon  a  clearly  marked 
edge  of  some  object,  distant  from  100  to  500  feet;  then  with  the  hand, 
carefully  turn  the  telescope  half  way  around,  so  that  the  same  wire  is 
compared  with  the  object  assumed.  Should  it  be  found  above  or  below, 
bring  it  half  way  back  by  moving  the  capstan  head  screws  at  right 
angles  to  it,  remembering  always  the  inverting  property  of  the  eye 
piece;  now  bring  the  wire  again  upon  the  object,  and  repeat  the  first 
operation  until  it  will  reverse  correctly.  Proceed  in  the  same  manner 
with  the  other  wire  until  the  adjustment  is  completed.  Should  both 
wires  be  much  out,  it  will  be  well  to  bring  them  nearly  correct  before 
either  is  entirely  adjusted;  when  this  is  effected,  bring  the  wires  in  the 
center  of  the  field  of  view  by  the  other  capstan  screws.  The  inverting 
property  of  the  eye  piece  does  not  effect  this  operation,  and  the  screws 
are  moved  direct. 

To  test  the  correctness  of  the  centering,  revolve  the  telescope, 
and  observe  whether  it  appears  to  shift  the  position  of  an  object. 
Should  any  movement  be  perceived,  the  centering  is  not  perfectly 
effected. 

It  may  be  here  repeated,  that  in  all  telescopes,  the  position  and 
adjustment  of  the  line  of  collimation  depends  upon  that  of  the  object 
glass;  and,  therefore,  that  the  movement  of  the  eye  piece  does  not 
affect  the  adjustment  of  the  wires  in  any  respect. 


J.    C.    SALA,    SAN    FRANCISCO 


THE    SURVEYORS'   COMPASS. 


53 


One  of  the  oldest  of  instruments  for  ranging  lines,  the  compass 
has  at  last  come  to  be  regarded  as  of  little  value  in  accurate  work.  In 
running  old  lines  however,  and  for  work  of  a  preliminary  nature,  it  is 
safe  to  say  the  compass  will  never  be  supplanted.  There  are  certain 
classes  of  work,  requiring  speed  rather  than  accuracy,  which  are  very 
satisfactorily  performed  by  means  of  the  compass,  and  to  supply  the 
demand,  I  keep  a  good  stock  of  all  kinds. 

THK  XKKDI.K.  All  compass  work  depends  upon  the  accuracy 
with  which  the  needle  reads.  It  is  essential  therefore  that  the  needle 
l>e  of  hard  steel  and  tempered  throughout  to  retain  its  magnetism.  It 
should  be  thin  and  at  the  same  time  have  enough  surface  to  be  strongly 
magnetic. 

The  needle  should  be  perfectly  straight  and  the  two  points  should 
read  precisely  180°  different  in  any  part  of  the  box.  It  should  be  so 
sensitive  that  when  drawn  away  from  its  pointing  by  a  piece  of  metal, 
it  will  always  return  to  the  same  reading  when  the  attraction  is  with- 
drawn. Four  things  affect  the  sensitiveness  of  a  needle;  the  form  of 
the  pivot  on  which  it  swings,  the  sharpness  of  the  pivot,  the  strength 
of  the  magnetism,  and  the  bearing  on  the  jeweled  pivot. 

When  a  needle  is  sluggish  it  should  be  lifted  off  the  pivot  and  the 
point  of  the  pivot  examined  with  a  glass;  if  it  is  dull  or  bent,  take  a 
fine  oil  stone,  and  holding  it  against  the  point  at  an  angle  of  about 
25°,  turn  the  compass  slowly  on  its  center.  This  will  grind  a  good 
point  if  carefully  done.  If,  after  ascertaining  that  the  point  is  sharp, 
the  needle  is  still  not  sensitive,  it  may  then  need  to  be  remagnetized. 
If  the  pivot  point  is  bent  or  not  truly  ground,  the  two  ends  of  the 
needle  will  not  read  180°  different;  to  preserve  it,  the  needle  should 
always  be  screwed  up  when  the  instrument  is  carried. 

As  the  generally  accepted  theory  is  that  a  needle  retains  its  mag- 
netism longer  when  lying  in  the  meridian,  it  is  well  to  always  let  the 


54  ILLUSTRATED    CATALOGUE   OF 


needle  swing  freely  when  the  instrument  is  not  in  use,  taking  care  to 
keep  the  instrument  level  so  the  needle  can  not  bend  the  pivot.  A 
quivering  motion  in  the  needle  when  swinging  freely,  is  a  very  good 
indication  that  it  is  well  made,  the  center  of  gravity  being  low. 

REMAGNETIZING.  To  remagnetize  a  needle,  take  it  off  the  pivot 
and  hold  the  south  end  in  the  left  hand;  take  a  good  magnet  in  the 
other  hand  and  place  the  positive  end  on  the  needle.  Draw  the  magnet 
slowly  toward  the  north  end  and  clear  off  the  needle.  Return  it  in  a 
large  circle  back  to  the  starting  point  and  repeat  the  operation  until 
the  work  is  done. 

Never  rub  a  magnet  back  and  forward  on  a  needle. 

ERRORS  IN  THE  INSTRUMENT.  To  determine  whether  the  com- 
pass itself  has  iron,  in  it,  set  three  stakes  in  the  ground  in  the  form  of  a 
triangle.  Set  on  one  and  read  the  angle  (preferably  10  or  15  degrees) 
between  the  other  two.  Take  this  angle  on  different  parts  of  the  grad- 
uated circle,  and  if  the  reading  is  the  same  at  all  points  there  is  no 
local  attraction  in  the  instrument. 

In  a  compass  attached  to  a  transit,  it  is  a  good  plan  after  setting 
the  instrument  so  that  both  compass  needle  and  vernier  read  0,  to  go 
round  the  circle,  setting  the  vernier  ten  degrees  ahead  each  time,  and 
noting  whether  the  compass  needle  also  describes  an  arc  of  precisely 
ten  degrees;  if  it  does  not,  there  is  some  attraction  in  the  instrument. 

A  fine  coil  of  wire  is  placed  on  the  south  end  of  needles  used  in 
the  northern  hemisphere  to  balance  them;  this  wire  must  be  shifted  as 
the  compass  is  changed  to  another  latitude,  and  in  the  southern  hemis- 
phere must  be  placed  on  the  north  end  of  the  needle. 

GRADUATIONS.  The  graduations  on  the  compass  box  should 
begin  at  the  north  point,  and  run  90°  in  both  directions;  then  decrease 
to  0  again  at  the  south  point.  In  order  that  the  needle  reading  may 
indicate  the  direction  of  the  telescope,  the  lines  joining  the  zeros  of  the 
ordinary  compass  ring  must  be  in  the  same  vertical  plane  with  the  line 
of  collimation  of  the  telescope,  and  the  letters  denoting  the  cardinal 
points,  east  and  west,  must  be  transposed;  /.  <?.,  when  the  letter  N  is 
towards  the  north,  the  letter  W  should  be  towards  the  east. 

The  needle  always  indicates  magnetic  north,  and  in  the  case  of 


J.    C.    SALA,    SAN    FRANCISCO  55 

instruments  unprovided  with  means  of  setting  off  the  local  variation 
of  the  needle,  all  the  readings  of  the  needle  must  be  corrected  for  this 
local  deviation. 

In  some  compasses  the  graduations  begin  at  0  at  the  north  end 
and  run  to  360  in  the  direction  of  the  movements  of  the  hands  of  a 
clock;  this  guards  against  reading  N  for  S,  B  for  W,  and  vice  versa. 


VERNIER    COMPASS,    No.    14-PRICE   $50. 

Surveyors'  compass,  5^-inch  needle,  i4-inch  plate,  vernier  to  set 
off  the  magnetic  variation  of  the  needle,  two  levels  with  ground  bubbles. 
Open  sights,  which  enable  more  accurate  observations  to  be  taken  than 
with  the  ordinary  sights.  Brass  head  tripod.  Cherry  box,  with  strap. 


No.    15-Plain  compass,  plate  12  inches  long,  open  sight,  needle 
inches  long,  two  levels,  Jacob   staff  mountings.     Cherry  box,  wit: 
strap.     Price  $35.00. 


ILLUSTRATED    CATALOGUE   OF 


CLINOMETER  COMPASS,  No.   16— PRICE  $55. 


This  instrument  is  very  useful  for  mining  and  for  road-making; 
the  sights  are  placed  0  inches  apart,  having  a  slot  for  straight  lines,  a 
cross  and  a  pin  hole  at  each  end  for  leveling  purposes,  a  quadrant 
divided  into  half  degrees,  with  pointer  and  clamp  to  hold  it  in  any 
position.  Perpendicular  angles  can  be  taken  with  this  instrument. 
Compass  divided  in  half  degrees,  needle  3^  inches  long.  Ball  and 
socket  with  brass  head  tripod.  The  instrment  is  packed  in  a  small 
portable  box,  with  strap. 


J.    C.    SALA,    SAN    FRANCISCO 


57 


SURVEYORS'  POCKET  COMPASS,  No.  17- 
PRICE  $25. 

With  extra  plate  to  set  off  variation  of  the 
needle,  two  spirit  levels,  needle  4*4  inches  long, 
with  Jacob  staff.  In  my  compasses,  the  variation 
is  put  on  top  of  the  ring,  which  allows  it  to  be 
read  more  easily. 

The  same,  with  brass  head  tripod,  price  $30.00. 

No.  18 — The  same,  but  one  inch  smaller,  with 
Jacob  staff.  Price  $20.00. 


SOLAR    COMPASS,    No.    19— 
PRICE   $220. 

The  horizontal  plate  of  this 
instrument  is  6^  inches  in  diam- 
eter, and  the  lower  plate  is  12 
inches  long.  The  plate  has  one 
double  vernier  reading  single 
minutes,  the  declination  and 
latitude  arcs  are  also  provided 
with  verniers  reading  single 
minutes.  The  length  of  needle 
is  4  inches.  The  instrument  is 
furnished  with  ball  and  socket, 
and  with  leveling  screws  which 
can  be  used  separately  or  together. 
All  the  graduations  are  on  Solid 
Silver.  The  instrument  is  small, 

compact  and  very  strong,  and  obviates  the  necessity  of  carrying  a  much 

heavier  instrument. 

A  telescope  can  be  attached  to  this  instrument  if  desired. 


ILLUSTRATED   CATALOGUE   OF 


THE     SOLAR    COMPASS. 


As  the  principal  objections  to  the  magnetic  needle  arise  from  the 
fact  that  the  needle  is  easily  attracted  from  its  true  direction  by  the 
near  presence  of  metal,  the  solar  compass  was  invented;  by  it,  true 
lines  are  run  from  observations  on  the  sun,  but  its  use  is  restricted  to 
sunshiny  days  and  certain  hours  of  the  day. 

The  first  practical  solar  compass  was  invented  by  William  A. 
Burt  of  Michigan,  and  patented  by  him  in  1836.  The  principle  con- 
sists in  a  practical  scientific  application  of  the  principles  which  govern 
the  motion  of  the  sun,  that  when  the  instrument  is  placed  in  adjust- 
ment, and  the  sun's  image  brought  to  a  certain  place,  the  instrument 
must  necessarily  be  in  the  meridian.  This  is  indicated  by  the  zeros  of 
the  horizontal  plates,  and  any  other  angle  can  be  read  off  by  graduated 
plates.  As  solar  work  can  only  be  performed  in  clear  weather,  the 
instrument  is  furnished  with  needle  and  graduated  plates. 

As  first  made,  the  solar  was  without  tangent  screws,  and  with 
ordinary  ball  and  socket  motion,  being  made  as  simple  as  possible  for 
use  in  the  wooded  brush  country  where  the  government  surveys  were 
then  made.  Since  then,  and  with  the  progress  of  surveys  into  more 
op ^n  country,  the  tangent  screws  and  the  transit  tripod  have  been 
added. 

When  the  weather  is  clear,  the  solar  compass  works  with  much 
greater  rapidity  than  either  compass  or  transit.  With  ordinary  care, 
and  instrument  in  adjustment,  its  result  should  not  vary  in  rapid  work 
more  than  from  one  to  two  minutes  from  the  correct  line,  a  result 
unattainable  in  the  ordinary  compass,  and  requiring  careful  work  to 
ensure  in  long  continued  lines  with  transit. 

MOUNTINGS.  Compasses  are  mounted  on  a  Jacob  staff,  which  is 
a  single  sharp-pointed  leg  to  thrust  into  the  ground,  or  on  tripods. 

The  larger  compasses  generally  have  telescopes  instead  of  open 
sights. 


J.    C.    SAI.A,    SAN    FRANCISCO 


ADJUSTMENTS    OF    THE    SOLAR 
COMPASS. 


1.  To  make  the  plane  of  t lie  bubbles  perpendicular  to  the  vertical 
axis.  This  is  done  by  reversals  about  the  vertical  axis,  whereby 
the  error  is  doubled,  and  at  the  same  time  made  apparent. 

'2.  To  adjust  the  lines  of  collimation.  The  declination  arm  has 
two  lines  of  collimation  established  by  a  lens  and  a  graduated  disk  at 
either  end  of  the  arm.  The  lens  at  the  arc  and  vernier  end  is  for  the 
north  declination  from  March  2()th  to  September  20th,  for  the  south 
declination,  September  20th  to  March  20th,  the  declination  arm  is 
revolved  180°.  This  adjustment  consists  in  making  the  two  lines  of 
collimation  parallel  to  each  other;  to  accomplish  this,  an  adjuster  is 
necessary,  and  therefore  this  part  of  the  adjustment  is  generally  left  to 
the  instrument  maker. 

To  make  the  declination  arc  read  zero  when  the  line  of  colli- 
mation is  at  rig/it  angles  to  the  polar  axis.  Set  the  vernier  on  the 
declination  arc  to  read  zero;  by  the  latitude  arc  bring  the  line  of  colli- 
mation upon  the  sun.  When  carefully  centered  on  the  disk,  revolve 
the  arm  quickly  ISO0  about  the  polar  axis,  and  observe  if  the  image 
now  falls  exactly  on  the  other  disk;  if  not,  move  the  declination  arm  by 
means  of  the  tangent  screw  until  the  image  falls  exactly  on  the  disk. 
Read  the  declination  arc,  loosen  the  screws  in  the  vernier  plate  and 
move  it  back  one-half  its  distance  from  the  zero  reading.  Center  the 
image  again,  reverse  180°  and  test.  Repeat  until  by  reversing,  the 
image  falls  in  the  center.  If  the  vernier  scale  is  not  adjustable  one-half, 
the  total  movement  is  the  error  of  the  declination  arc.  Make  this 
adjustment  when  the  sun  is  near  the  Zenith. 

5.  To  adjust  the  vernier  of  the  latitude  arc.  Find  the  latitude 
of  the  place  either  from  a  good  map,  compound  it  from  table  No.  XI 
by  a  sextant  or  transit  observation.  Set  up  the  compass  a  few  minutes 
before  noon,  with  the  true  declination  (compounded  for  that  day  from 
the  Kphemeris)  set  off.  Bring  the  line  of  collimation  upon  the  sun, 


6o 


ILLUSTRATED    CATALOGUE   OF 


having  it  clamped  in  the  plane  of  the  sights  or  at  the  twelve-hour 
angle,  and  follow  it  by  moving  the  latitude  arc  by  means  of  the  tangent 
screw,  and  by  turning  the  instrument  on  its  vertical  axis.  When  the 
sun  has  attained  its  highest  altitude,  read  the  latitude  arc;  compare 
this  with  the  known  latitude,  correct  on  the  vernier  if  possible,  if  not, 
record  the  error. 

Other  adjustments  being  either  the  same  as  in  the  limbs  of  the 
transit  or  belonging  entirely  to  the  instrument  maker's  resort,  I  omit 
them  here. 


PRISMATIC    COMPASS,   No.    20— PRICE    $15. 


This  compass  is  3  inches  in  diameter,  with  divided  ring  on  needle 
and  folding  sights;  packed  in  neat  case,  very  convenient  for  recon- 
noissance.  Prices  range  between  $15  and  $48. 


J.    C.    SALA,    SAN    FRANCISCO 


6l 


POCKET    COMPASS,  No.   21. 


These  compasses  have  folding  sights.     Prices  range  between  $fi.OO 
and  $25.00. 


62 


ILLUSTRATED   CATALOGUE   OF 


THE    PLANE    TABLE— No.   22. 


J.    C.    SALA,    SAN    FRANCISCO 


THE    PLANE    TABLE. 


This  instrument  is  made  by  me  in  two  sizes.  Size  1  has  a  larger 
base  for  the  table  to  rest  on  than  is  usual  in  plane  tables,  and  therefore 
is  particularly  adapted  for  the  more  accurate  work  in  topographical 
surveying.  For  work  of  a  more  general  character,  where  greater 
portability  is  required,  I  make  this  base  of  the  ordinary  size,  like  those 
used  in  the  U.  S.  Coast  Survey,  but  with  all  the  improvements  of  the 
larger  base.  One  tangent  screw  is  attached  to  the  lower  part,  and  this, 
as  well  as  the  alidade,  is  built  on  the  skeleton  plan,  so  as  to  make  them 
light  and  stiff.  The  alidade  is  provided  with  a  powerful  telescope, 
striding  level,  vertical  arc,  small  round  level  and  stadia  wires,  and  is  so 
arranged  that  lines  can  be  ruled  in  the  vertical  plane  of  the  line  of 
collimation  of  the  telescope. 

Price  of  plane  table  No.  1 ,  including  table,  detached  compass, 

2  cases,  screw-drivers,  clamps,  etc.,  $275.00 

Price  of  plane  table  No.  2  (size  usually  made),  250.00 


The  plane  table  is  the  instrument  used  almost  exclusively  by  the 
U.  S.  Coast  and  Czeodetic  Surveyors  for  filling  in  of  the  topographical 
charts. 

Plane  table  complete  with  achromatic  telescope  11  inches  long, 
with  sunshade,  object  glass  1  ^-inch,  with  rack  movement;  spiral 
adjustment  to  eye  piece,  magnifying  about  twenty-four  times.  The 
telescope  revolves  on  axis  mounted  in  standards  6^  inches  high,  with 
arc  graduated  to  half  degrees,  vernier  reading  to  one  minute.  Alidade 
18  inches  long,  two  inches  wide,  one  edge  beveled.  Detachable  table 
!Sx24  inches,  mounted  on  tripod  by  a  large  plate,  resting  on  three 
leveling  screws.  Either  compass  with  3-inch  or  4^-inch  needle,  plumt 
bob,  plumbing  bar  and  universal  level. 


64  ILLUSTRATED    CATALOGUE   OF 


ADJUSTMENTS    OF    THE    PLANE 
TABLE. 


The  adjustment  of  the  alidade  being  the  same  as  the  adjustment 
of  the  telescope  and  vertical  arc  in  the  transit,  I  refer  to  the  adjust- 
ment of  the  transit  for  these  adjustments.  There  is  only  one  other 
adj  ustment. 

Jo  make  the  axis  of  the  plate-bubbles  parallel  to  the  plane  table. 
Level  the  table  with  the  alidade  in  any  position,  noting  the  readings  of 
the  bubbles,  mark  the  exact  position  of  the  alidade  on  the  table,  take 
it  up  carefully  and  reversing  it  end  for  end,  replace  it  by  the  same 
marks.  If  the  bubbles  now  have  the  same  reading  as  before,  with 
reference  to  the  table,  they  are  parallel  to  the  plane  of  the  table;  if  not, 
adjust  the  bubbles  for  one- half  the  movement  and  try  again. 


J.    C.    SAI.A,    SAN   FRANCISCO 


THE    SEXTANT,    No.    23. 

The  radius  of  the  sextant  is  7  inches,  145°;  four  sun-glasses 
between  the  large  and  the  small  reflecting  mirror,  and  three  sun-glasses 
behind  the  small  reflecting  mirror,  all  of  which  can  be  turned  on  their 
axis  ISO0.  Graduation  on  Solid  Silver,  reading  to  10";  telescope 
34 -inch  aperture;  two  astronomical  eye  pieces  with  powers  of  6  and 
10  dia.  One  Galilean  telescope  with  extra  large  objective,  power 
8  dia.;  one  fixed  reading  glass;  two  sights  for  examination  and  correc- 
tion of  the  large  reflecting  mirror.  All  complete  in  box.  Best  quality, 
imported. 

Price,  as  above,          ......        $130.00 

radius  10  inches,  .  .  150.00 


ARTIFICIAL    HORIZON. 

Mercury  Horizon,  of  boxwood,  with  silver-plated  coppery 
bowl;  bottle  of  boxwood  for  mercury;  brass  rectangular  I 
roof  with  glass  covers  made  of  parallel  glass.  All  | 
complete;  packed  in  box.  Best  quality,  imported,  .  J 


50.00 


ILLUSTRATED    CATALOGUE 


SEXTANTS. 


In  addition  to  the  ordinary  sextant  in  general  use  on  board  ships, 
I  keep  on  hand  the  pocket  sextant,  especially  designed  for  the  use  of 
civil  engineers  in  hydrographic  surveying,  locating  of  buoys  or  sound- 
ings, also  in  reconnoissance  work,  explorations  and  preliminary  surveys. 
This  sextant  is  made  of  brass,  is  about  3  inches  in  diameter,  1^-inch 
deep,  and  has  a  brass  lid  which  entirely  covers  it  when  not  in  use.  It 
reads  angles  to  half  a  minute.  Price  $43.00. 


ADJUSTMENTS   OF   THE   SEXTANT. 


1.  To  make  the  index  glass  perpendicular    to  the  plane  of  t/ic 
sextant.     Bring  the  vernier  to  read  about  30°,  and  examine  the  arc  and 
its  image  in  the  index  glass  to  see  if  they  form  a  continuous  curve.     If 
the  glass  is  not  perpendicular  to  the  plane  of  the  arc,  the  image  will 
appear  above  or  below  the  arc,  according  as  the  mirror  leans  forward  or 
backward.     It  is  adjusted  by  slips  of  thin  paper  under  the  projecting 
points  and  corners  of  the  frame. 

2.  To  make  the  horizon  glass  parallel  to  the  index  glass  for  a 
zero-reading   of  the  vernier.     Set  the  vernier  at  zero  and  see  if  the 
direct  and  reflected  images  of  a  well  denned  distant  object  as  a  star, 
comes  into  exact  coincidence;    if  not,   adjust  the  horizon  glass  until 
they  do. 

3.  To  make  tlic  plane  of  sight  of  the  telescope  parallel  to  the 
plane  of  the  sextant.     The  recticule  in  the  sextant  carries  four  wires 
forming  a  square  fn  the  center  of  the  field;  the  center  of  this  square  is 
iu  the  line  of  collimation  of  the  instrument.     Rest  the  sextant  on  a 
plane  surface,  pointing  the  telescope  upon  a  well  defined  point  some 


J.    C.    SALA,    SAN    FRANCISCO 


67 


twenty  feet  distant.  Place  two  objects  of  equal  height  upon  the  extrem- 
ities of  the  limb  that  will  serve  to  establish  a  line  of  sight  parallel  to 
the  limb;  two  lead  pencils  of  same  diameter  will  serve,  but  they  had 
better  be  of  such  height  as  to  make  this  line  of  sight  even  with  that  of 
the  telescope.  If  both  lines  of  sight  come  upon  the  same  point  to 
within  half  an  inch  or  so  at  a  distance  of  twenty  feet,  the  resulting 
maximum  error  in  the  measurement  of  an  angle  will  be  only  \" '. 


OPTICAL    SQUARE. 

The  optical  square  is  a  small  hand  instrument  to  set  off  right 
angles  in  full  in  setting  off  offsets. 


FIG.  25. 


FIG.  20. 


THE    TELEMETER,  No.   24-PRICE   $18. 


This  is  an  exceedingly  clever  little  instrument,  invented  by 
Labbez,  and  is  designed  to  give,  without  any  calculation  whatever, 
the  distance  of  objects  from  250  to  3,000  yards.  It  is  most  simple  in 
construction,  easily  understood,  very  accurate,  and  not  likely  to  get 
out  of  order.  The  chief  merits  claimed  for  it  are,  that  it  does  not 
require  much  training  to  use  it,  nor  is  it  necessary  that  an  absolute 


68  ILLUSTRATED    CATALOGUE    OF 

right  angle  be  laid  out.  and  it  is   not   dependent   on   seeing   a  definite- 
sized  object  (such  as  a  man  standing  erect.) 

The  following  are  the  directions  for  using  the  instrument  : 

1 .  Open  the  slide  at  end  of  cylinder. 

2.  Set  the  small-toothed  wheel  so  that  the  zero  is  opposite  zero- 
line,  also  set  the  revolving  part  of  the  cylinder  so  that  the  zero  on  it  is 
exactly  on  the  zero-line  of  fixed  portion  of  cylinder. 

3.  To  find  the  distance  of  A  (Fig.  27),  stand  at  D,  face  to  the 
left,  E,   and  notice  an  object  (say  B)  of  a  prominent  nature   (known 
hereafter  as  the  mark)  as  near  as  possible  at  right  angles  to  the  object 
A  of  which  the  range  is  required.     Hold   the  instrument  with  the 
thumb  and  finger  of  the  left  hand,  as  shown  at  Fig.  26,  in  such  a  way 
that  the  oblong  opening  is  quite  free,  and  place  it  to  the  eye ;  look 
through  the  hole  at  the  small  end  of  the  instrument  at  mark  B,  and 
with  the  forefinger  of  the  right  hand  turn  the  small-toothed  wheel  until 
coincidence  between  the  range  object  A  and  the  mark  B  is  obtained — in 
other  words,  A  is  reflected  on  B. 

4.  Fasten  the  end  of  the  line  into  the  ground  at  D  by  passing  one 
of  the  arrows  through  the  loop  and  walk  to  the  other  end  (c)  of  the 
30-yard  line  in  the  direction  of  B.     Let  someone  standing  exactly  over 
D  dress  the  observer  exactly  with  B   (by  calling  out  quarter  or  half 
pace,  &c.,  right  or  left,  until  the  right  side  of  head  of  observer  covers 
the  mark  B.) 

5.  The  observer,  facing  the  same  way  as  in  previous  operation, 
now  looks  at  B   revolving  the  end  of  cylinder  until   the  object  A  is 
reflected  on  B. 

Directly  this  is  done  the  line  opposite  the  fixed  zero  will  repre- 
sent the  distance  of  the  object  A  in  yards. 

Should  it  so  happen  (and  the  occurrence  would  be  very  rare) 
that  no  natural  or  other  prominent  object  is  to  be  found  somewhere 
near  at  right  angles  to  A  to  use  as  a  mark,  then  a  man  can  run  out 
with  a  lance,  rifle,  &c.,  and  place  himself  at  any  position  near  the  right 
angle  at  any  distance  over  BO  yards. 

The  observation  may  be  made  the  reverse  of  above  if  no  suitable 
object  is  found  to  the  left  (see  Fig.  28).  The  only  thing  is  to  turn 


J.    C.    SALA,    SAN    FRANCISCO  69 


the  instrument  over  and  follow  the  same  instructions  as  previously 
given,  reading  "right"  for  "left." 

The  base  may  be  paced,  instead  of  measured,  when  approximate 
accuracy  is  sufficient,  and  time  is  of  consequence. 

The  length  of  base  may  be  half  (viz.  15  yards)  or  double 
(60  yards),  and  the  results  will  be  half  and  double  respectively  of  the 
distances  shown  on  the  drum  of  instrument. 

Observations  may  be  checked  by  stopping  at  15  when  using  the 
30  base,  and  taking  an  observation  there. 

If  no  second  person  is  at  hand  to  dress  the  observer  with  the 
mark  B,  and  greater  accuracy  is  required  than  can  be  obtained  by  walk- 
ing straight  by  the  eyesight  in  the  direction  of  B,  the  following  plan 
may  be  resorted  to  :— 


-~    c 


B 

E  D  D        E 

FIG.  28. 


laying  out  the  &w<?.— Note  the  object  you  intend  taking  as  a 
mark  about  at  right  angles  to  the  object,  then  walk  about  33  paces  in 
the  direction  of  it,  see  that  nothing  obscures  the  object  or  mark,  and 
place  a  sword  or  picket  through  loop  of  line  ;  now  return,  unwinding 
the  30  yards  of  line  as  you  go,  and  when  at  the  end  move  right  or  left 
until  the  picket  is  aligned  on  mark.  Then  proceed  as  in  previous 
directions,  paragraphs  i,  2,  3,  at  this  point  (D),  and  on  going  to  c  turn 
cylinder  until  object  and  mark  coincide.  Read  off  the  distance  in 
yards  opposite  zero. 

When  time  is  of  consequence  very  good  results  can  be  obtained 
by  walking  the  equivalent  number  of  paces  to  30  yards  in  the  direction 


70  ILLUSTRATED    CATALOGUE   OF 

of  mark,  placing  the  picket  or  sword,  and  pacing  the  same  number 
back,  taking  mean  of  error  in  doing  so,  and  aligning  picket  as  before. 

Another  plan  for  use  by  one  person  only: — 

(This  illustration,  Fig.  28,  is  shown  the  reverse  way  to  that  gen- 
erally adopted  ;  that  is,  looking  right  instead  of  left. ) 

1.  Use   a   line    15  yards  long,    and  place  an  arrow    or  picket 
through  the  loop  of  it  at  E.     Set  the  instrument  to  zero  as  before,  and 
looking  through  it    in    direction  of  B  see  what    object  will  coincide 
nearest  with  the  reflection  of  A. 

2.  Walk  to  end  of  the  lint  at  D,  and,  moving  right  or  left,  stop 
when  E  is  aligned  with  B,  and  place  a  mark  or  picket  in  that  position, 
then  look  through  the  instrument  and  turn  small-toothed  wheel  until 
A  is  exactly  reflected  on  mark  B. 

3.  Now  take  the  line,  and  walking  past  D  stop  at  extremity 
of  it  (c),  when  E  and  D  are  aligned,  right  about  turn  very  exactly  so  as 
not  to  shift  the  position. 

4.  Face  B,  and  on  looking  through  the  telemeter  rotate  the  end 
of  cylinder  until  A  is  reflected  on  B.     The  range  can  now  be  set  off 
opposite  the  zero. 

In  rotating  the  cylinder  it  is  better  to  stop  exactly  at  the  point 
where  the  object  aligns  the  mark  ;  and  if  it  goes  beyond,  then  it  should 
be  turned  back  and  gradually  brought  up  to  the  mark  again.  This 
precaution,  although  not  absolutely  necessary,  ensures  greater  accuracy. 

If  time  permits,  a  second  observation  can  be  taken,  and  the  mean 
of  the  two  readings  taken  as  the  distance  of  object  A. 

The  use  of  the  Labbez  telemeter  as  a  surveying  instrument. — The 
instrument  will  determine  the  distance  apart  of  two  inaccessible  objects 
by  laying  out  a  triangle  as  follows  : 

Let  A  and  B  be  two  points  inaccessible  from  point  C.  Having 
measured  with  the  telemeter  the  distance  c  A  and  c  B,  carry  on 
in  these  two  directions  proportional  lengths  c  B'  and  c  A'. 

The  triangle  A'  BX  c  being  similar  to  the  triangle  ABC,  one  has 
A  B  =  A'  B'  X  -( 

C   B' 

A'  B'  is  known  as  it  can   be  measured  directly,  and   the  product 

O    T? 

is  an  equality  of  it. 
C   B 


J.    C.    SALA,    SAN    FRANCISCO 


29 


30-31 


32 


33 


g! 

34 


35 


LEVELING    RODS. 


No.  29.  NKW  YORK  ROD,  with  my  improved  clamp,  preventing 
the  defacing  of  the  divisions,  target  provided  with  good  rim  protecting 
the  painted  face.  Target  vernier  reading  to  lOOOths.  Satinwood, 
sliding  out  to  12  feet.  Price  $14.00. 

No.  30.  PHILADELPHIA  ROD,  made  of  the  best  cherry  wood, 
thoroughly  seasoned;  the  face  is  accurately  divided  by  machine  to" lOOths 
of  a  foot,  with  improved  target  divided  to  read  to' lOOOths  of  a  foot. 
Price  SI  7. 00. 

No.  31.  PHILADELPHIA  ROD,  as  above,  but  divided  in  lOths  of  a 
foot,  with  vernier  reading  to  2()0ths  of  a  foot.  Price  $14.00. 

No.  32.  ENGLISH  SELF-READING  ROD,  telescoping  with  strong 
brass  mounting,  5  feet  long,  slides  out  to  14  feet.  Price  $27.00. 

No.  33.  LINK  RODS  of  best  wood,  8  ft.  long  with  steel-pointed  shoe, 
and  divided  red  and  white  alternately,  each  $2.50  ;  10  feet  long,  $3.00. 

No.  34.  STEEL  LINE  RODS  7  feet  long,  size  5/s  of  an  inch, 
painted  red  and  white,  each  $3.00. 

No.  35.  IRON  TUBULAR  ROD,  J/s  inch  diameter  steel  shoes, 
painted  red  and  white  alternately  every  foot.  Price  $3.00, 


72  ILLUSTRATED    CATALOGUE   OF 

No.  36.  SALA'S  SELF-READING  ROD,  8  feet  long  ;  divided  in 
feet,  lOths  and  lOOths  of  a  foot,  with  red  numbers  at  each  foot,  no 
target,  very  convenient  for  quick  work.  Price  $4.00. 

No.  37.     The  same,  but  double,  sliding  out  to   15  feet,  $10.00. 


4 

8= 

8 


FLYNN'S    COMBINED    TRANSIT    AND    LEVEL    ROD,    No.   38— 
PRICE    $5.00. 


The 


This  rod  is  merely  a  combination  of  two  old  rods  into 
one.  I  am  making  these  rods  after  a  pattern  supplied  to  me 
by  P.  J.  Flynn,  civil  engineer,  who  has  used  it  on  railroad 
construction  and  found  it  very  useful  for  that  work.  By  its 
use  one  rod  can  be  dispensed  with  under  certain  circum- 
stances, as  in  railroad  construction,  running  contour  and 
grade  lines,  etc.,  by  transit  with  level  attachment. 

This  rod  is  1^  inches  wide,  ^  inch  thick,  and  8  feet  or 
more  in  length,  as  may  be  required.  One  end  is  shod  with 
iron  like  an  ordinary  level  rod ;  the  other  end  is  tapered  to  a 
point  and  has  a  steel  shoe  pointed  at  one  end  secured  to  it. 
From  the  point  of  this  steel  shoe  to  the  middle  of  the  other 
end  of  the  rod,  a  straight  line  is  drawn,  and  on  each  side  of 
this  line  the  rod  is  painted  alternately  red  and  white  at  every 
foot;  this  side  forms  the  transit  rod.  On  the  back  of  rod, 
that  is  on  the  face  of  the  level  rod,  and  about  3^  feet  from 
the  steel  point  a  small  level  is  held,  to  show  when  the  center 
line  of  the  rod  is  vertical,  and  by  this  level  the  rodman  can 
keep  his  rod-plumb  even  when  he  is  so  situated  that  he  cannot 
see  the  transit-man;  and  the  transit-man,  if  he  is  able  to  see 
two  feet  of  the  rod  above  an  obstruction,  can  fix  a  point  and 
take  an  observation  with  precision. 

The  other  side  of  the  rod  is  graduated  as  a  .self-reading 
level  rod  from  the  shoe  upwards  into  feet  and  tenths, 
half- tenths  and  hundredths,  as  may  be  required.  This  rod 
can  then  be  used  with  either  transit  or  level,  and  can  also  be 
used  when  chaining  on  steep  ground  as  a  plumb. 

No.  39.  P'LEXIBLE  POCKET  LEVELING  ROD,  10  feet 
long,  3  inches  wide,  divided  like  self-reading  rod  to  lOths  and 
lOOths  of  a  foot.  Made  of  pliable,  strong,  rubber  canvas. 
Can  be  coiled  up  and  carried  in  pocket.  For  use,  it  is 
fastened  to  a  board  or  stick  with  thumb  tacks.  Price  $3. 25; 
12  feet  long,  $4.00;  14  feet  long,  $4.50;  3  meters  long, 
$3.25;  4  meters  long,  $4.00. 
above  rods  are  also  divided  in  inches  and  ^  inch  at  same  price. 


METRIC     RODS    ALWAYS     ON     HAND. 


J.    C.    SALA,    SAN    FRANCISCO 


73 


SURVEYORS'   CHAINS,  No.  40. 

These  are  all  standard  chains  with  three  oval  rings. 

Iron  Chain,  Brass  Handles,  No.  8  wire,    33  feet $  2  60 

3  25 

4  oo 

5  25 

3  50 

4  25 

6  50 

8  oo 


Steel  Chains, 


8 

"  10  " 

"    10  " 

11  10  " 

"    10  " 


50 

66 

100 

33 
50 
66 

IOO 


brazed  links  and  ring,  No.  12  wire,    33  feet 5  5° 


12 
12 

12 


50  ' 

66     " 

IOO      " 


Meter  Chains  always  on  hand.  Iron  Arrows,  No.  8  wire,  11  in 
set ,  1 8  inches 

Steel  Arrows,  Xo.  10  wire,  n  in  set,  12  inches,  50  cts.,  75  cts-> 
$1.00  and  $1.25. 


6  oo 

10  oo 

11  50 

i  25 


74 


ILLUSTRATED    CATALOGUE    OF 


CHESTERMAN'S    STEEL    TAPES,   No.   41. 

In  leather  case,  with  flush  handles. 

25  feet $  4  50  66  feet 3  8  oo 

33    "   5  oo  75 

50    "   


6  oo 


100 


9  oo 
10  oo 


CHESTERMAN'S    METALLIC    TAPES,   No.   42. 


33  feet. 
50     "   . 

66     "   . 


..$2    25 

••   2  75 
..  3  oo 


75  feet. 

IOO      "     . 


•$3  75 
•   4  50 


J.    C.    SALA,    SAN    FRANCISCO 


75 


PAINE'S    PATENT    STEEL    TAPES,   No.  43. 

In  leather  case,  with  flush  handles. 


33  feet $5  oo  75  feet. 

50    "   6  oo  100    "   . 

66    "   7   50 


.$  9  oo 


EDDY'S   IMPROVED  STANDARD  STEEL  TAPES,  No.  44. 

Metal   lined  with   flush   handles,   in   leather-covered   case,  graduated 
in  icths  or  i2ths  of  a  foot  or  metric  measure. 


Feet 33  5O 

Price,   each $5-5O        6.75          8.25          9-75 


100 

12.00 


76 


ILLUSTRATED   CATALOGUE   OF 


THE    RIVAL    STEEL    TAPE,    No.    45. 


The  Rival  is  made  of  the  best  steel  ribbon  of  sufficient  width 
(^  inches)  and  thickness  to  insure  strength  and  durability,  yet  light 
enough  not  to  require  a  cumbersome  case.  The  steel  ribbon  is  etched 
to  such  a  depth  as  to  let  the  marks  appear  as  if  embossed,  thus  guar- 
anteeing their  distinctness  after  years  of  hard  service.  The  case  is 
made  of  stout  brass,  nicely  nickel  plated  and  is  more  durable  than  any 
other  used  ;  it  is  compact  in  form,  and  the  handle  folds  nearly  flush 
with  the  case.  I  respectfully  invite  a  critical  comparison  of  the  Rival 
steel  tape  with  the  cheaper  grades  extensively  advertised  and  quoted  at 
a  similar  price.  A  comparison  will  show  that  the  Rival  rests  upon  its 
intrinsic  merits  as  a  reliable,  low-priced  tape. 

Rival  Steel,     50  feet  long,  in   loths  or  i2ths $4  oo 

"        75     "       "  "  "  ••••   5  50 


100 


oo 


STEEL    TAPES    OF    ANY    DESIRED    LENGTH    MADE    TO    ORDER. 


J.    C.    SAI.A,    SAN    FRANCISCO 


77 


METALLIC    WARP    TAPES,   No.  46. 

These  tapes  are  made  of  the  best  linen  tape  with  wire  threads  to 
prevent  stretching,  and  by  our  process  of  making  are  always  soft  and 
pliable.  The  ends  are  reinforced  with  leather  to  prevent  wearing,  and 
all  the  cases  have  our  new  improved  flush  handle.  Graduated  in  loths, 
with  links  on  opposite  side. 


Metallic  Tape,   ^  inch  wide. 

Feet 25  33          40 

Price,  each $1.30 


33 
1.50 


50 

2.00 


66 
2.30 


75 
2-75 


100 

3.10 


Invented  by  Ernest  McCullough,  Civil  Engineer. 

PATENT    TAPE    LEVEL,  No.   47— PRICE   $1.00. 


This  little  device,  a  California  production,  is  meeting  with  deserved 
favor  wherever  used.  The  above  cut  is  full  size  ;  the  weight  of  the 
level  is  only  one  ounce.  It  is  used  by  clamping  to  the  tape,  about  one 
foot  from  the  handle,  by  means  of  the  two  springs  shown,  and  can  be 
attached  and  detached  instantly. 


ILLUSTRATED    CATALOGUE   OF 


POCKET     LEVEL,    No.    48. 

Bubble  mounted  in  lacquered  brass  tube  upon  brass  base. 

3  6  9  12  inch. 

$  -5°  i.oo  r-75  2-5° 

Extra  fine  ground  spirit-level,   mounted  in  bell-metal  tube  and 
rendered  adjustable  to  the  base  by  capstan  screws  ;  very  delicate. 

6  9  12  inches. 

$7.50  9.00  10.50 


LOCKE'S    HAND    LEVEL,   No.   49. 

Bronze,  in  good  leather  case 


oo 


ABNEY'S    REFLECTING    LEVEL,   No.   50— PRICE    $13.50. 

Abney's  Reflecting  Level  or  Pocket  Altimeter,  improved,  combin- 
ing the  uses  of  both  "Locke's  Hand  Level"  and  "Clinometer,"  in 
leather  or  mahogany  box. 

No.  51.  Same  as  above,  but  with  compass  and  socket  for  Jacob 
staff.  Price,  $16.00. 


J.  c.  SAtA,  SAN  FRANCISCO 


79 


SALA'S    TELESCOPIC    HAND    LEVEL,  No.  52. 

The  Sala  Hand  Level  is  an  entirely  new  instrument,  and  consists 
of  a  telescope  magnifying  six  times.  The  tube  is  provided  with  the 
level  and  prism  usual  in  other  hand  levels.  In  the  tube  is  fixed  a 
diaphragm  with  stadia  wires  adjusted  to  the  ratio  of  one  foot  to  fifty 
feet,  thus  enabling  an  engineer  to  quickly  measure  distances  in  prelim- 
inary surveying.  The  eye  piece  and  object  glass  are  adjustable  as  in 
ordinary  transit  telescopes.  Price,  with  bather  case,  $15.00. 


BOXWOOD  CLINOMETER  RULE,  No.  53-PRICE  $11.50. 

Superior  12  inch,  attached  compass  E,  two  bubbles  C  and  D, 
folding  sights  A  B,  and  arc  F  of  90°,  for  each  degree  of  which  the 
corresponding  rates  between  horizontal  distance  and  rise  or  fall  is  found 
upon  the  inclination  scale  G  ;  in  morocco  case. 


So  ttUJSTRATUD    CATALOGUE   OP 


THE    ATTWOOD    CLINOMETER. 

No.    54. 


This  is  a  very  useful  and  practical  instrument  for  the  use  of  the 
miner,  prospector,  millman  and  foreman  of  mines.  It  is  light  and  can 
be  carried  in  the  pocket.  With  the  aid  of  a  small  straight-edge,  any 
inclination  or  angle  can  be  determined.  It  is  admirably  adapted  for 
the  arranging  of  sluices  and  setting  of  amalgamating  plates  or  timber- 
ing in  drifts  or  inclines  in  a  mine. 


SALA'S    ALUMINUM    CLINOMETER,  No.   55. 

My  Aluminum  Clinometer  is  an  improvement  on  the  Attwood 
Clinometer  in  so  far  as  it  is  lighter  and  not  liable  to  warp  when  alter- 
nately exposed  to  damp  and  very  dry  atmospheres.  Another  peculiarity 
consists  in  the  disposition  of  the  sights,  which  are  inserted  in  the  short 
narrow  upright  sides,  which  disposition  affords  them  greater  protection; 
also  the  adaptation  of  the  dial  and  the  compass  box  of  the  same,  on  the 
face  of  the  instrument,  is  novel.  The  horizontal  and  vertical  levels  are 
inserted  in  the  top  and  side  faces  as  they  are  in  the  Attwood  Clinometer. 
The  size  of  the  instrument  is  6x3^ x^  inches,  making  it  small  enough 
to  be  carried  in  the  pocket.  Price,  in  leather  case,  $15.00. 


J.    0.    SAtA,    SAN   FRANCISCO 


81 


SALA'S  ODOMETER,  No.  56- 
PRICE   $17.00. 

For  measuring  distances  by  a  wagon.  It 
is  enclosed  in  a  brass  box,  4^  inches 
diameter,  furnished  with  leather  case  with 
double  straps  to  fasten  to  the  center  of  the 
wheel.  It  is  the  most  correct  Odometer  in 
practical  use. 


PEDOMETERS,   No.   57. 


Pedometers  are  pocket  instruments  for  measuring  the  distance 
traversed  in  walking,  the  number  of  miles  being  registered  by  a 
mechanism,  inclosed  in  a  nickel-plated  watch  casing,  and  operated  by 
the  motion  of  the  body.  Directions  accompany  each  instrument. 

Watch  size,  registering  20  miles  and  divided  in  %  of  mile $  5  oo 

The  same,  with  three  faces  and  hands,  registering  single  steps...     9  oo 
Passometer,  watch  pattern,  nickel  case,  with  three  hands,  regis- 
tering 25,000  steps I0  °° 


ILLUSTRATED    CATALOGUE   OF 


PLUMB    BOBS,    No.    58. 

Plumb  Bobs  of  the  most  improved  shape  with  steel  point,  frc 
ii.oo  to  $5.00,   according  to  size  and  weight. 


J.    C.    SALA,    SAN    FRANCISCO 


C.    SALA'S    ILLUMINATED     PLUMB    BOB, 

No.    59— Price    $10   and    $12. 


9 


Patented   October  3oth,    1883. 


This  simple  instrument,  which  supplies  a  long 
felt  want  among  civil  and  mining  engineers,  contains 
within  itself,  lamp  and  lantern  combined.  The  Plum- 
met, which  is  chambered  for  the  purpose  at  the  top,  is 
the  lamp,  and  all  the  parts  are  firmly  secured  together, 
giving  an  absolute  solidity  to  the  whole. 

All  the  work,  being  done  upon  the  lathe,  is  con- 
centric, securing  a  perfectly  vertical  line  through  the 
point,  the  lamp  and  the  point  of  suspension.  The 
difficulties  of  protecting  the  flame  from  flaring  and 
those  arising  from  the  non-adjustment  of  the  point  and 
the  flame,  which  are  experienced  in  the  best  lamps 
heretofore  constructed,  wherein  the  lamp  is  suspended 
by  chains,  are  entirely  obviated. 

To  light  the  lamp  it  is  only  necessary  to  slide  up 
the  glass  which  forms  the  lantern  and  apply  the  match. 
The  conical  top  of  the  lantern  protects  the  light 
against  water  dropping  from  the  roof  of  the  mine  or 
tunnel. 

It  is  admirably  adapted  for  use  in  mills  and  manufactories  where 
shafting  is  laid. 

Special  diploma  awarded  by  the  Mechanics'  Institute,  San  Fran- 
cisco, 1883. 

Size  No.  1,  weighs  2%  Ibs.;  size  No.  2,  weighs  \%  Ibs. 


84  ILLUSTRATED    CATALOGUE  OF 


SURVEYING  ANEROID   BAROMETERS,  WITH  VERNIER  READING 

TWO    FEET. 

No.  60 — Purveying  Barometer,  brass  case,  5  inch  diam- 
eter, silvered  dial,  division  on  raised  ring, 
fixed  altitude  scale  15,000  feet,  vernier  scale 
operated  by  rack  and  pinion,  reading  to  one 
foot,  compensated  for  temperature,  adjust- 
able reading  lens,  in  leather  sling  case each,  $50  ()( 

No.  61 — Surveying  Barometer,  brass  case,Q  inch  diam- 
eter, silvered  dial,  division  on  raised  ring, 
fixed  altitude  scale  10,000  feet,  vernier  scale 
operated  by  rack  and  pinion,  reading  to  five 
feet,  compensated  for  temperature,  adjust- 
able reading  lens,  in  leather  sling  case 47  0( 


J.    C.    SALA,    SAN    FRANCISCO 


ANEROID    BAROMETERS. 


FOR    MEASURING    HEIGHTS    AND    ATMOSPHERIC 

PRESSURE. 


No.  62 — Pocket  pattern,  bronzed  case,  2^  inch  diametei, 
silvered  dial,  revolving  altitude  scale  from 
Sooo  to  16,000  feet.  Revolving  altitude 
scale  compensated  for  temperature.  In 
morocco  case,  price from  $20  to  $30 

No.  63 — Pocket  pattern,  gilt  case,  1^  inch  diameter,  sil- 
vered dial,  revolving  altitude  scale  8000  feet, 
compensated  for  temperature.  In  morocco 
case,  price from  $10  to  $20 


86 


ILLUSTRATED   CATALOGUE   OF 


ACHROMATIC   FIELD   AND   MARINE   GLASSES. 
Manufactured    by    the    Societe    d'Optique,    Paris. 

No.  64.  Field  or  Marine  Glasses,  black  kid  body  with  sun- 
shades, finely  japanned  or  oxidized  draw- tubes,  cross-bars,  tops  and 
trimmings;  in  sole  leather  sling  case: 

21  24  26  lignes. 

$14.00  16.00  18.00 

Manufactured  by  Bardou,  Paris. 

No.  65.  Field  or  Marine  Glasses,  black  morocco  body  with  sun- 
shades, oxidized  draw-tubes,  cross-bars,  tops  and  trimmings;  in  sole 
leather  sling  case: 


24 

J2I.OO 


26  lignes 
24.00 


No.  66.     Field  or  Marine  Glasses,  as  above,  with  12  lenses: 
24  26  lignes. 


$25.00 


28.00 


J.    G.    SALA,    SAN    FRANCISCO 

ACHROMATIC  FIELD  AND   MARINE  GLASSES-Continued. 

No.  67.  Field  or  Marine  Glasses,  with  jointed  cross-bars,  afford- 
ing adjustment  for  pupillary  distance: 

2  4  26  iignes. 

$25.00  28.00 

Manufactured  by  Lemaire,  Paris. 

No.  68.  Field  or  Marine  Glasses,  superior,  U.  S.  Signal  Service, 
black  morocco  body  with  sun-shades,  finely  black  japanned  or  oxidized 
draw-tubes,  cross-bars,  tops  and  trimmings;  in  sole  leather  sling  case  : 

24  26  Iignes. 

$18.00  20.00 

No.  69.  Field  or  Marine  Glasses,  as  above,  with  jointed  cross- 
bars, affording  adjustment  for  pupillary  distance,  26  Iignes $28.00 

No.  70.  Field  or  Marine  Glasses,  black  morocco  body  with  sun- 
shades, black  japanned  or  oxidized  draw-tubes,  cross-bars,  tops  and 
trimmings  in  morocco  sling  case  : 

15  17  19  21  24  26  28  Iignes. 

$9.00         10.00         11.00         12.00         13.00         14.00       25.00 

No.  71.  Field  or  Marine  Glasses,  as  above,  with  12  lenses;  sole 
leather  case,  26  Iignes $21.00 

No.  72.  Field  or  Marine  Glasses,  black  morocco  body  with  sun- 
shades, black  japanned  or  oxidized  draw-tubes,  tops  and  trimmings; 
jointed  cross-bars,  affording  adjustment  for  pupillary  distance;  in  sole 

leather  sling  case  : 

24    •  26  Iignes. 

$21.00  22.50 

No.  73.      Field  or  Marine  Glasses,  black  morocco  body  with  sun- 
shades, finely  black  japanned  or  oxidized  draw-tubes,  cross-bars  and  hie 
tops,  compact  model,  designed  to  afford  large  field,  in  morocco  sling  case: 
I5  1 7  19  21  24  26  Iignes. 

$11.00  12.00  13-00  14-00  15-00  16.00 


88  ILLUSTRATED   CATALOGUE   OF 


BINOCULAR    TELESCOPES,  No.  74. 


These  glasses  have  great  power,  and  where  objects  are  fully 
illuminated,  they  are  unequaled.  They  are  provided  with  hinge  or 
joint,  and  can  be  adjusted  to  the  different  widths  of  eyes,  thereby 
securing  a  perfectly  even  field,  and  avoiding,  when  looked  through,  all 
strain  to  the  ocular  muscles. 

The  performance  of  a  glass  of  this  kind  is  equal  to  a  spy-glass  of 
very  much  greater  power,  because,  by  the  use  of  both  eyes,  the  field  of 
vision  or  amount  of  scenery  which  a  person  sees  at  one  time  is  wonder- 
fully increased.  Complete  with  sun-shades,  case,  strap,  etc. 

Binocular  Telescope,  as  above,  n  lignes $  50  oo 

i3     "     55  oo 

15     "     • 65  oo 


ALUMINUM     BINOCULAR     TELESCOPES, 

No.    75. 


ii  lignes,  same  as  above $  75  oo 

13  "    "      "  85  oo 

15  "  "  : 100  oo 

17  "    "      "  115  oo 


J.    C.    SALA,    SAN    FRANCISCO 


89 


SPY- GLASSES,    No.    76. 


First  Quality.     11   Lignes,  Equal  to  One  Inch 


Spy-glasses  3  draws,   black   morocco  body,   stitched,  burnished 
brass  draw  tubes. 


DIMENSIONS. 

Full  Length,         Closed, 
Inches.              Inches. 

Diameter  of 
Object    Glass, 
Lignes. 

Magnifying 
Power, 
Times. 

Range, 

Miles. 

PRICE. 

C  I/ 

5/4 

IO 

10 

5 

$2    50 

lf>X 

6 

II 

15 

6 

3  °° 

i6X 

6 

12 

15 

6 

3  50 

r; 

6^ 

13 

2O 

7 

4  oo 

•634 

2O 

8 

4  50 

23 

8 

16 

25 

9 

6  oo 

30 

IO 

10 

30 

IO 

8  oo 

Spy-glasses,  4  draws,  with  sun-shade  to  extend  over  object  glass; 
black  morocco  body,  burnished  draw  tubes. 


DIM  EN}- 

Full  Length, 
Inches. 

IONS. 

Closed, 
Inches. 

Diameter  of 
Object    Glass, 
Lignes. 

Magnifying 
Power, 
Times. 

Range, 
Miles. 

PRICE. 

36 

45'-- 

I0# 

1234 

22 
25 

40 
45 

H 

18 

$16  50 
23  50 

The  above  are  very  superior  glasses  for  terrestrial  observations, 
and  afford  excellent  views  of  the  sun,  moon,  Satellites  of  Jupiter,  etc. 
To  produce  the  best  results,  they  should  be  used  on  a  tripod  stand. 

Tripods  for  any  spy-glass,  nicely  made 


oo 


POCKET    MAGNIFIERS,    No.    77. 

Rubber  case,  size  of  lens  i  inch  diameter  ................................  $°  5° 

«      i     "  "       ................................       75 


lenses  i  /s  and  i  #  inch  diameter  ...............   i  25 

Shell  case,  size  of  lens  i#  inch  diameter  ................................   T  3° 

«'  "         lenses  i      and  i  ^  inch  diameter  ..................   i  ^o 


ILLUSTRATED  CATALOGUE  OF  J.  C.  SAL  A,  S.  F. 


GOSSAMER    AND    SILK    BAGS. 

Gossamer  or  water-proof  bag,  to  cover  transit  or  level  in  case  )  # 

c         •  i  (.   •#*    *•    ^^ 

of  rain  or  dust )~ 

Silk  bag,  to  cover  transit,  with  solid  graduations i   oo 

LUBRICANTS. 

Bottle  of  fine  watch  oil,  for  lubricating  transit  centers,  etc $o  25 

"       vaseline   for  lubricating   level   centers,    leveling   and  ) 
tangent  screws,  etc ( 

UTENSILS    FOR    CLEANING   INSTRUMENTS. 

Camel's  hair  brush $o  40 

Stiff  brush  for  cleaning  screw-threads 40 

Chamois-skin  for  cleaning  lenses,  centers,  etc 50 

Stick  for  cleaning  centers 50 


ROD    LEVEL,  No.  78-PRICE   $3.50. 

This  contrivance  consists  of  a  Universal 
level  and  a  V  shaped  handle.  The  shape 
of  the  handle  permits  one  to  use  the  rod 
level  on  any  round,  prismatic  or  angular  pole. 


TIMBER  SCRIBER,  No.  79— PRICE  $1.25. 

Tool  for  surveyors  to  mark  stakes,  bearing 
trees,  etc. 

STEPHENS'    COMBINATION    RULE,    No.    80— 
PRICE    $2.00. 


ROD  LEVEL. 


IMPROVED  CAMERA  LUCIDA,  No.  81— 
PRICE   $10.00. 

With  double    sliding   tubes   and  clamp;  in 
mahogany  case. 


Surveyors'  Engineers'  Architects' 

and     Draughtsmen's 

Office  Requisites 


PART   B 


J.    C.    SALA,    SAN    FRANCISCO 

7O 


DRAWING     MATERIALS. 


Drawing  boards  from  75  cents  each,  for  small  work,  to  any  size  and 
price  desired.  Constructed  of  sound,  seasoned  wood. 

Trestles  and  horses  for  drawing  boards  furnished  to  order.  Folding 
trestles  and  cases  of  drawers  also  furnished.  Send  for  plans  and 
prices. 

Drawing  papers  of  all  standard  makes  and  names,  in  sheets  and  rolls. 
Detail  papers,  tracing  papers,  tracing  cloth,  profile  and  cross-section 
paper  in  sheets  and  rolls,  kept  on  hand  and  sent  upon  order  at 
regular  catalogue  prices  of  all  dealers. 

Sample  books,  with  prices,  15  cents. 


BLUE    PRINT    PAPERS. 


Any  make  of  the  standard  blue  print  papers  can  be  furnished  at 
the  catalogue  price  of  the  maker.  Also  blue  print  frames  and  all 
appliances  for  the  work. 

To  make  blue  print  copies  of  tracings.  As  some  customers  off  in 
the  country  are  called  upon  for  blue  print  copies  occasionally  and  cannot 
wait  for  the  supplies  to  arrive  from  San  Francisco,  and  besides  may  not 
have  enough  calls  for  such  work  to  warrant  them  in  keeping  a  supply 
on  hand  at  all  times,  the  following  directions  for  making  their  own 
paper  may  be  useful. 

1st.     The  paper  should  be  a  good  quality  of  book  paper. 

•2cl.       The  Mixture.     This  consists  of  equal  parts,  by  weight,  of 
citrate  of  iron  and  ammonia,  and  red  prussiate  of  potash.     These  may 
be  procured  from  any  druggist.     They  are  mixed  in  the  proper* 
one  ounce  of  citrate  of  iron  and  ammonia  and  one  ounce  of  red  pn 
siate  of  potash  to  eight  ounces  of  water.     Put  in  a  stone  bottle  (to  1 


94  ILLUSTRATED   CATALOGUE   OF 

from  the  light)  and  shake  well.     In  ten  minutes  they  will  be  dissolved. 

3d.  Lay  the  paper  which  is  to  be  treated,  on  a  smooth  table  or 
board.  Pour  some  of  the  sensitizing  solution  in  a  shallow  dish,  as  a 
plate  or  saucer,  and  with  a  broad  brush  like  a  soft  copying-press  brush, 
apply  a  good  even  coating  of  the  solution  to  the  paper.  When  the 
paper  is  coated,  tack  it  to  a  board  and  put  it  in  a  dark  place  to  dry,  an 
operation  which  wall  take  about  an  hour. 

4th.  To  Print.  Upon  a  smooth  board  tack  two  or  three  thick- 
nesses of  flannel  or  blanket,  and  be  careful  that  they  are  not  wrinkled. 
Lay  on  the  cloth  the  sheet  of  sensitized  paper  with  the  coated  surface 
up;  upon  this  lay  the  tracing,  and  great  care  must  be  exercised  that 
the  paper  and  tracing  are  also  very  smooth,  as  a  wrinkle  will  spoil  the 
work.  Upon  the  tracing,  lay  a  piece  of  heavy  plate  glass.  The  fore- 
going operations  must  be  conducted  in  a  dark  room.  The  glass  must 
be  heavy  to  keep  the  paper  smooth.  After  the  glass  is  in  position, 
bring  the  board  out  to  the  light  and  put  it  in  the  place  it  is  to  remain 
while  printing. 

5th.  Within  an  hour  or  two  of  noon  during  the  summer  time, 
from  six  to  ten  minutes  will  suffice  for  an  exposure.  Karlier  or  later 
in  the  morning  it  will  take  longer  to  make  a  good  print,  and  if  the  day 
is  cloudy  or  the  drawing  cannot  be  exposed  directly  to  the  sun,  it  may 
take  from  half  an  hour  to  one  or  two  hours  to  secure  a  good  print. 
Experience  will  soon  enable  one  to  do  good  work. 

6th.  Washing.  After  the  print  has  been  exposed  a  sufficient 
time,  take  it  from  under  the  glass  and  place  in  a  sink  or  shallow  box 
filled  with  cold  water.  Let  it  soak  for  a  few  minutes  and  then  wash  it 
thoroughly.  The  lines  of  the  drawing,  faintly  visible  up  to  this  time, 
will  appear  in  clear  white  lines  upon  a  blue  ground.  After  washing, 
tack  it  up  against  a  wall  or  hang  by  the  corners  from  a  line  to  dry. 
The  operation  is  then  finished. 

7th.  To  write  with  a  white  line  upon  a  blue  print,  use  a  solution 
of  common  soda  with  an  ordinary  pen. 


Papers  and  material  also  kept  for  positive  black  printing  processes, 
which  some  prefer  to  bhie  prints. 


J.    C.    SAI.A,    SAN   FRANCISCO 


95 


Engineers'   Field  Books  for  transit,  level,  topography  and  stadia 
work,  kept  on  hand  or  made  to  order  at  regular  catalogue  prices. 

Lead  Pencils  of  all  the  best  makes  furnished  when  called  for. 


THE    PLANIMETER,    No.    82. 


The  polar  planimeter  is  used  for  computing  with  rapidity  and 
accuracy,  the  area  of  any  figure,  how  irregular  it  ever  may  be,  such  as 
railroad  profiles,  indicator  diagrams,  plots  of  ground,  etc.,  etc.,  and  is 
of  great  value  to  engineers  and  others  on  account  of  its  saving  in  time 
and  labor. 

Amsler's  polar  planimeter,  German  silver,  in  case $27  50 


Pantographs  of  any  make  can  be  furnished  to  order  at  regular 


prices. 


PROTRACTORS,  No.   83-PRICE   FROM   $1.00  to  $6.00. 

Plain  circular  and  semi-circular  protractors,  German  silver,  bras* 
or  horn,  divided  to  #,  %,.  3ti4  single  degree. 


96 


ILLUSTRATED   CATALOGUE   OF 


KERN'S    SWISS    PROTRACTORS,   WITH    ARM    AND    VERNIER, 

No.   84. 


Semi-circular  German  silver  Protractor,  5^ -inch,  divided  to  ) 

*/z  degrees,  with  arm  and  vernier,  reading  to  3  minutes...  j 

Semi-circular  German  silver  Protractor,  8-inch,  divided  to  ^  I 

degrees,  with  arm  and  vernier,  reading  to  1  minute ( 

Semi-circular  German  silver  Protractor,  10-inch,  divided  to  ^  ( 

degrees,  with  arm  and  vernier,  reading  to  1  minute j 

Circular  German  silver  Protractor,    5^ -inch,    divided  to    */,  / 

degrees,  with  arm  and  vernier,  reading  to  3  minutes ( 


Circular   German    silver    Protractor,    8-inch,    divided   to    ^ 
degrees,  with  arm  and  vernier,  reading  to  1  minute 

Circular   German   silver    Protractor,    10-inch,  divided   to    ^ 


$n  oo 


14  oo 


17  oo 


14  oo 


1 6  oo 


•         TO     OO 

degrees,  with  arm  and  vernier,  reading  to  1  minute $ 

Morocco  silk  velvet-lined  cases  for  above,  $3.50  to  $4.50. 


DRAUGHTSMEN'S    PROTRACTORS,    No.    85. 

This  Protractor  is  made  from  Vl6-inch  sheet  steel  and  is  light  and 
durable.  The  length  of  the  blade  is  8>4  inches.  The  graduations 
read  to  degrees  and  the  vernier  reads  to  5  minutes. 

This  Protractor  is  chiefly  used  in  connection  with  a  T  square  or 
straight  edge.  It  can  be  quickly  and  accurately  set  by  hand  to  any 


J.    C.    SALA,    SAN    FRANCISCO 


97 


angle.      A  lever  is,    however,   provided  as  of  possible  advantage  in 
obtaining  very  fine  settings. 

There  are  no  projections  on  -ither  face  of  the  Protractor,  and, 
consequently,  it  can  be  used  on  either  edge  of  the  blade  or  either  side 
up.  This  makes  it  particularly  convenient  in  dividing  circles,  trans- 
ferring angles,  drawing  oblique  lines  at  right  angles  to  each  other,  or 
laying  off  given  angles  each  side  of  a  vertical  or  horizontal  line  without 
changing  the  setting. 

In  many  instances  the  Protractor  takes  the  place  of  the  ordinary 
4.V:lc-»-R.'e  and  (iO-degree  triangle,  and  it  is  also  used  as  an  extension  to 
the  T  square  when  the  work  is  beyond  the  end  of  the  blade  of  the 
square. 

Draughtsmen's  Protractor,  in  morocco  case,  velvet-lined  ...........  $9  oo 

no  case  .........................................   7  50 


Boxwood    and     Ivory     Protractors. 

catalogue  prices. 


Any    make    at    regular 


k  j,    A    J»    'J 

IP    .jo    iji    jg    j 

1     i      5J5     5(6      5 

HH 

»    cp 

fflffl 

^ 

'             n 

€                    5 

*                 13 

2 

1                          « 

3/tj. 

5 

L^ST 

1                                     91 

1          9 

i 

L 

L' 

03 

'IN 

M 

%I 

FLAT    SCALES,    No.    86. 

Ivory  and  boxwood  flat  chain  scales,  for  engineers  and  architects, 
from  $1.00  to  $8.00.     Special  divided  scales  made  to  order. 


TRIANGULAR    SCALES,    No.    87. 

Patent  Metallic  Scales,  12  inches  long,  for  architects  or  engineers, 
price  $:-J.OO. 

Boxwood  Scales,  for  architects  or  engineers,  12-inch  $1.50;  18-inch 
$2..">0;  24-inch  $4.25. 

Triangular  Scale  Guard,  25  cents. 


98  ILLUSTRATED    CATALOGUE   OF 


MANNHEIM    SLIDE    RULE,   No.   88-PRICE  $4.50. 

10-inch  long,   divided   on  celluloid  tacing,  with   brass  indicator,   also 
directions  for  using. 

STADIA  SLIDE   RULE,   No.   89— PRICE  $13.50. 

20-inch,  celluloid  face. 


STRAIGHT  EDGES,   No.    90. 

Steel  nickel  plated: 

24  30  36  42  48  60  72  inches 

$2.00         3.00         4.00  5-oo         6.00          8.50         12.  oo 

Celluloid  edged: 

24  30  36  42  48  inches 

$1.00         1.25          1.50         1.80          2.20 

T    SQUARES,   WOOD,  No.   91. 

According  to  size,  from  ...........................................  25cts.  to  $1.50 

With  shifting  head,  according  to  size,  from  ..................  $1.25  "      3.00 

TRIANGLES,    No.    92. 

Steel  nickel  plated,  45°:     8  10  12  inches 

$4.25  5.50  6.50 

Steel  nickel  plated,   30°  and  60°:     8  10  15  inches 

$3.85  4.25  6.50 

PARALLEL    RULERS,    No.    93. 

Ebony  folding:      6  9  12  15  18  24  inches 

3oc         55c  ysc  9oc         $1.10         2.20 


Rolling  brass:                       12  15  18  inches 

$9.00  10.50  12.00 

Rolling  ebony:                      12  15  18  inches 

$5.00  6.50  7.50 


J.    C.    SALA,    SAN    FRANCISCO 


99 


Drawing  instruments,  colors,  brushes,  and  all  the  one  thousand  and 

one  little  office  necessities  for  engineers',  surveyors'  and 

draughtsmen's  use,  kept  constantly  on  hand 

and    furnished     on     demand. 

Prices  the  same  as  all  dealers'  catalogues. 

Mention  name   of  dealer,  date   of  catalogue,  name  and 

number   of  article  wanted  when   ordering. 


IN  OTI  C 


I  am  prepared  to  manufacture  on  short  notice, 
to  order,  any  scientific  instruments  applied 
to  astronomy,  navigation,  physics,  or  chem- 
istry appertaining  to  my  line  of  business. 

J.    C.    SALA. 


Miscellaneous 
Scientific    Instruments  . 


PART   C 


J.    C.    SALA,    SAN    FRANCISCO 


I03 


ASTRONOMICAL  TELESCOPE,  No.  94— PRICES  $50  to  $200. 


Body  with  finder  and  movements  of  highly  finished  lacquered 
brass,  rack  and  pinion  for  adjustment  of  focus;  object-glass  3;^  inches 
in  diameter,  two  terrestrial  eye-pieces  with  sun-glass  powers  of  75,  100 
and  lo()  diameters;  packed  in  strong  walnut  case,  with  lock  and  key. 
The  telescope  is  mounted  upon  a  very  fine  polished,  firm  mahogany 
tripod  stand,  with  folding  legs,  and  can  be  adjusted  to  any  desired 
height  by  a  rack  and  pinion  operated  by  a  crank. 

Heliographs  for  signaling  by  day  or  night,  complete $45.00 


IO4 


ILLUSTRATED   CATALOGUE   OF 


SALA'S    STANDARD    RAIN    GAUGE,   No.   95— PRICE    $3.00. 

The  utility  of  knowing  the  rainfall  of 
any  locality  is  sufficiently  obvious,  and 
little  need  be  said  upon  the  subject.  The 
rain  gauge  should  be  in  the  hands  of 
every  gardener  and  farmer. 

In  the  management  of  out-door  plants 
and  crops,  as  well  as  in  the  maintenance 
of  cisterns  and  tanks  for  the  supply  of 
water,  a  rain  gauge  is  a  valuable  assistant. 
By  its  use  the  gardener  will  be  guided  in 
judging  how  far  the  supply  of  moisture 
to  the  earth  is  needed,  and  he  will  also 
see  how  beneficial  is  even  a  hasty  shower 
to  growing  plants  when  he  considers  that 
a  fall  of  rain  measuring  the  tenth  of  an 
inch  in  depth  corresponds  to  the  deposit 
of  about  forty  hogshead  per  acre, 

The  study  of  the  rainfall  of  a  country 
is  of  considerable  interest  to  agricultur- 
alists. The  health  and  increase  of 
domestic  animals,  the  development  of 
the  productions  of  the  land,  as  well  as 

the  daily  labors  of  the  farmer  are  dependent  upon  the  excess  or 
deficiency  of  rain.  The  statistics  of  rainfall  are  not  only  valuable  and 
interesting,  from  a  meteorological  point  of  view  and  for  agricultural 
purposes,  but  are  also  highly  important  in  connection  with  sanitary 
arrangements  for  towns  and  engineering  operations;  this  is  especially 
evident  to  the  hydraulic  engineer. 

As  rain  is  an  important  source  of  water  supply  to  rivers,  canals 
and  reservoirs,  it  is  evident  that  a  knowledge  of  the  probable  fall  of 
any  season  or  month  at  a  given  place,  as  furnished  by  averages  of  the 
observations  of  former  years,  will  be  the  data  upon  which  the  engineer 
will  base  his  plans  for  providing  for  floods  or  droughts,  while  the 
measurement  of  the  actual  quantity  which  has  just  fallen,  as  gathered 


J.    C.    SALA,    SAN    FRANCISCO  IQ{. 


from  indications  of  a  series  of  gauges,  will  suggest  to  him  the  precau- 
tions to  adopt,  either  to  economize  or  to  conduct  away  the  inflowing 
waters. 

This  rain  gauge  is  made  of  metal,  is  simple,  and  cannot  get  out 
of  order.  It  consists  of  four  pieces: 

a.  The  overflow,  a  galvanized  iron  cylinder  12  inches  long  and 
3  inches  in  diameter,  holding  10  inches  of  rain. 

b.  The  copper  receiver,  which  catches  all  the  rain  to  be  measured. 

c.  The  brass  measuring  cylinder  connecting  with  the  copper 
receiver. 

d.  The  black  walnut  measuring  rod  having  ten  inches  divided 
into  one  hundred  parts;  measuring  as  one  inch  the  rainfall  to  that 
degree  of  accuracy. 

<?.     The  outlet. 

Directions  for  use.  In  an  unsheltered  open  level  space,  sink  the 
overflow  to  half  its  depth  and  support  it  so  it  will  not  get  upset.  If 
more  than  one  inch  of  rain  falls,  it  runs  into  the  overflow.  Insert  the 
measuring  rod  which  wets  up  to  10,  that  is  one  inch,  the  surplus 
escaping  into  the  overflow;  if  less,  the  rod  will  be  wet  to  40  or  70  as 
the  case  may  be,  showing  so  many  hundreds  of  an  inch.  Pour  the 
water  out  from  the  brass  cylinder  and  pour  in  from  overflow  one  inch, 
or  parts  of  the  inch,  and  add  all  together,  which  gives  total  fall  from 
last  observation,  which  should  be  made  every  twenty-four  hours. 


GROUND    BUBBLES,   No.   96. 

Ground  Bubbles  of  all  sizes  for  engineers,  millwrights,  machinists 
and  carpenters. 


SALA'S  IMPROVED  EXTENSION  TRIPOD,  No.  97-PRICE  $14. 

This  tripod  is  the  best  for  stability,  and  the  legs  being  round, 
obviate  the  trouble  of  carrying  a  bulky  tripod,  with  sharp  corners.  It 
can  be  opened  to  5  feet  and  closed  within  34  inches. 


io6 


ILLUSTRATED    CATALOGUE    OF 


U.    S.    SIGNAL    SERVICE    MERCURIAL    STANDARD 
BAROMETER,    No.    98. 

Price,  in  sling  case $40  to  $75 


WEATHER   ANEROID   BAROMETERS, 
No.  99. 

In  brass  cases,  best  quality,  brass  dial: 

5  7  8  10  inches 


$12.00         17.00          25.00 


35-oo 

With  double  thermomete 


MASON'S  HYGROMETER,  No.  100- 
PRICE  $5.50. 

With  wet  and  dry  bulb  thermom- 
eters and  cistern,  mounted  and 
graduated  on  solid  boxwood,  with 
hygrometic  tables. 


U.  S.  Signal 
Service 
Mercurial 
Standard 
Barometer. 


THERMOMETERS,    No.    101. 
Vacuum  gauges  and  thermometers  for  sugar 
pan,  made  to  order. 

Maximum  thermometers .$o.o() 

Minimum  '2.00 

Six's  combined  maximum  and  minimum  ") 

thermometer,     10-ir>ch,     mounted     and  •     r  ~,. 
graduated  on  neatly  carved,  solid  box-  ' 
wood  back J 

Thermometers  and    Hydrometers  of  all  descrip- 
tion and  sizes. 


Papers    and    Tables 


PART    D 


IN  Selecting  Tables,  I  have  omitted 
all  those  contained  in  either  the 
"  Manual  of  Instructions "  pub- 
lished by  the  General  Land  Office 
of  the  United  States  or  those 
found  in  the  Nautical  Almanacs. 

J.    C.    SALA. 


J.    C.    SALA,    SAN    FRANCISCO 


THE   SAEGMULLER    SOLAR  ATTACHMENT. 

Patented    Ma>    3,   1881. 


J.     C.     SALA,     AGENT. 


This  attachment  to  the  regular  engineer's  transit,  by  means  of 
which  the  astronomical  meridian  may  be  obtained  in  a  few  minutes 
with  an  accuracy  scarcely  thought  to  be  possible,  has  met  with  such 
success  that  it  bids  fair  to  supersede  all  other  methods  for  the  determi- 
nation of  the  meridian  by  means  of  engineering  instruments. 

The  transit  has  come  to  be  the  universal  instrument  for  the 
engineer,  and  will  be  for  the  surveyor  sooner  or  later,  and  the  attach- 
ment of  the  solar  apparatus  to  the  transit  has  thus  become  a  necessity. 
Since  its  first  introduction,  this  attachment  has  been  greatly  improved, 
and  as  now  made,  is  well  nigh  perfect.  Attached  to  any  transit  which 
possesses  a  telescope,  level  and  a  vertical  circle,  it  will  give  the  meridian 
within  the  nearest  minute.  By  using  instruments  which  have  a  finer 
graduated  vertical  circle  and  better  levels  than  are  usually  found  on 
transits,  the  meridian  can  be  determined  with  greater  accuracy  still. 

Advantages  of  the  "Saegmuller  Solar  Attachment"  over  the  old 


First.     It  is  more  accurate. 

Second.     It  is  simpler  and  easier  of  adjustment. 

Third.  It  can  be  used  when  the  sun  is  partly  obscured  by  clouds, 
when  the  ordinary  "  solar  "  fails  altogether. 

Fourth.  It  can  be  used  where  the  sun  is  quite  close  to  the 
meridian. 

Fifth.     The  time  can  be  obtained  with  it  reliable  to  within  a  few 

seconds  with  perfect  ease. 

Sixth.     It  can  be  used  as  a  vertical  sighting  telescope. 

It  is  as  superior  to  all  forms  hitherto  used,  as  the  transit  is  to  the 
ordinary  compass,  or  as  a  telescope  is  to  common  sights. 

The  sights  of  an  ordinary  solar  compass  consist  merely  of  a  small 
lens  and  a  piece  of  silver  with  lines  ruled  on  it  placed  in  its  focus.  This 


110  ttLUSTRATED    CATALOGUE   OF 

is  simply  a  very, primitive  telescope,  since  the  exact  coincidence  of  tin 
sun's  image  with  the  lines  has  to  be  determined  by  the  unaided  eye,  o 
at  best  with  a  simple  magnifying  glass.  That  far  greater  precision  cat 
be  attained  by  means  of  a  suitable  telescope  is  obvious;  in  fact,  th< 
power  of  the  solar  telescope  is  in  keeping  with  the  transit  telescope,  a: 
it  should  be. 

A  glance  at  the  cut  will  show  that  the  ' '  Saegmuller  Solar  Attach 
ment ' '  is  far  simpler  than  the  ordinary  form.  By  raising  or  depress 
ing,  it  can  be  set  to  north  or  south  declination.  To  effect  this  with  th< 
ordinary  solar  compass,  two  sets  of  primitive  telescopes — one  answering 
for  north,  the  other  for  south  declination — are  required,  which  an 
difficult  to  adjust.  The  addition  of  the  level  on  the  solar  telescop< 
dispenses  with  the  declination  arc  altogether,  the  arc  or  circle  on  th< 
transit  also  serving  for  that  purpose  in  conjunction  with  it.  Th( 
' '  Saegmuller  Solar  Attachment "  is  in  fact  the  only  one  which  shoulc 
be  used  in  connection  with  a  transit  instrument.  //  solves  the  sola* 
problem,  as  has  been  attested  by  leading  astronomers  and  engineer* 
who  have  used  it. 

Prof.  J.  B.  Johnson,  of  Washington  University,  St.  Louis,  Mo. 
has  given  it  a  thorough  test,  and  writes  as  follows: 

"In  order  to  determine  just  what  accuracy  was  possible  with  a  Saegmulle: 
Solar  Attachment,  I  spent  two  days  in  making  observations  on  a  line  whose  azi 
muth  had  been  determined  by  observations  on  two  nights  on  Polaris  at  elonga 
tion,  the  instrument  being  reversed  to  eliminate  errors  of  adjustment.  Forty 
five  observations  were  made  with  the  solar  attachment  on  Oct.  24,  1885,  from  9  t< 
10  A.  M.,  and  from  1.30  to  4  P.  M.,  and  on  Nov.  7,  forty-two  observations  betweer 
the  same  hours. 

"On  the  first  day's  work  the  latitude  used  was  that  obtained  by  an  ob 
servation  on  the  sun  at  its  meridian  passage,  being  38°  39',  and  the  mean  azimutt 
was  20  seconds  in  error.  On  the  second  day,  the  instrument  having  been  more 
carefully  adjusted,  the  latitude  used  was  38°  37',  which  was  supposed  to  be  aboul 
the  true  latitude  of  the  point  of  observation,  which  was  the  corner  of  Park  and 
Jefferson  avenues  in  this  city.  It  was  afterwards  found  this  latitude  was  38°  37' 
15",  as  referred  to  Washington  University  Observatory,  so  that  when  the  mean 
azimuth  of  the  line  was  corrected  for  this  I5X/  error  in  latitude  it  agreed  exactly 
with  the  stellar  azimuth  of  the  line,  which  might  have  been  iox/  or  15' '  in 
error.  On  the  first  day  all  the  readings  were  taken  without  a  reading  glass, 
there  being  four  circle  readings  to  each  result.  On  the  second  day  a  glass 
was  used. 

"  On  the  first  day  the  maximum  error  was  4  minutes,  the  average  error  was 
0.8  minute,  and  the  'probable  error  of  a  single  observation'  was  also  0.8 
minute.  On  the  second  day  the  maximum  error  was  2.7  minutes,  the  average 


J.    C.    SALA,    SAN    FRANCISCO 


III 


error  was  I  minute,  and  the  '  probable  error  of  a  single  observation '  was  0.86 
minute.  The  time  required  for  a  single  observation  is  from  three  to  five  minutes. 

"  I  believe  this  accuracy  is  attainable  in  actual  practice,  as  no  greater  care 
was  taken  in  the  adjustment  or  handling  of  the  instrument  than  should  be  exer- 
cised in  the  field. 

' '  The  transit  has  come  to  be  the  universal  instrument  for  the  engineer,  and 
should  be  for  the  surveyor;  so  it  is  more  desirable  to  have  the  solar  apparatus 
attached  to  the  transit  than  to  have  a  separate  instrument.  The  principal  advan- 
tages of  this  attachment  are  : 

"  i.     Its  simplicity. 

"2.  Its  accuracy  of  pointing,  being  furnished  with  a  telescope  which  is 
accurately  set  on  the  sun's  disk. 

"3.  In  its  providing  that  all  angles  be  set  off  on  the  vertical  and  horizontal 
limbs  of  the  transit,  thus  eliminating  the  eccentricity  and  other  inaccuracies 
usually  found  in  attachment  circles  or  arcs. 

' '  4.     Its  small  cost. 

"  It  is  also  readily  removed  and  replaced  without  affecting  its  adjustments, 
and  is  out  of  the  way  in  handling  and  reversing  the  telescope.  It  may  be  at- 
tached to  any  transit." 


SAEGMULLER     SOLAR     ATTACHMENT. 

The  above  cut  represents  the  improved  "Saegmuller  Solar  At- 
tachment"  as  now  made.     It  consists  essentially  of  a  small  telescope 
and  level,  the  telescope  being  mounted  in  standards,  in  which  it  can  b 
elevated  or  depressed.     The  standard  revolves  around  an  axis,  c 
the  polar  axis,  which  is  fastened  to  the  telescope  axis  of  the  trans 
strument.     The  telescope  called  the   -  Solar  Telescope"  can  thus 
moved  in  altitude  and  azimuth.  Two  pointers  attached  to  the  telescope 


112  ILLUSTRATED   CATALOGUE   OF 


to  approximately  set  the  instrument  are  so  adjusted  that  when  th( 
shadow  of  the  one  is  thrown  on  the  other  the  sun  will  appear  in  the 
field  of  view. 

Adjustment   of    the   Apparatus. 

1.  The   transit   must  be  in  perfect  adjustment,   especially  th( 
levels  on  the  telescope  and  the  plates  ;  the  cross  axis  of  the  telescop< 
should  be  exactly  horizontal,  and  the  index  error  of  the  vertical  circl< 
carefully  determined. 

2.  The  Polar  axis  must  be  at  right  angles  to  the  line  of  colli 
mation  and  horizontal  axis  of  main  telescope. 

To  effect  this,  level  the  intstrument  carefully  and  bring  the  bubbl< 
of  each  telescope  level  to  the  middle  of  its  scale.  Revolve  the  sola- 
around  its  polar  axis,  and  if  the  bubble  remains  central  the  adjustmen 
is  complete.  If  not,  correct  half  the  movement  by  the  adjusting  screw! 
at  the  base  of  the  polar  axis,  and  the  other  half  by  moving  the  solai 
telescope  on  its  horizontal  axis. 

3.  The  line  of  Collimation  of  the  solar  telescope  and  the  axis  Oj 
its  level  must  be  parallel. 

To  effect  this,  bring  both  telescopes  in  the  same  vertical  plane 
and  both  bubbles  to  the  middle  of  their  scales.  Observe  a  mark  throng! 
the  transit  telescope,  and  note  whether  the  solar  telescope  points  to  £ 
mark  above  this,  equal  to  the  distance  between  the  horizontal  axis  o 
the  two  telescopes.  If  it  does  not  bisect  this  mark,  move  the  cross  wires 
by  means  of  the  screws  until  it  does.  Generally  the  small  level  has  nc 
adjustments  and  the  parallelism  is  effected  only  by  moving  the  cross- 
hairs. 

The  adjustments  of  the  transit  and  the  solar  should  be  fre- 
quently examined,  and  kept  as  nearly  perfect  as  possible. 

Directions  for  Using  the  Attachment. 

First.  Take  the  declination  of  the  sun  as  given  in  the  Nautical 
Almanac  for  the  given  day,  and  correct  it  for  refraction  and  hourly 
change.  Incline  the  transit  telescope  until  this  amount  is  indicated  by 


J.    C.    SALA,    SAN    FRANCISCO 


its  vertical  arc.  If  the  declination  of  the  sun  is  north,  depress  it ;  if 
south,  elevate  it.  Without  disturbing  the  position  of  the  transit  tele- 
scope, bring  the  solar  telescope  into  the  vertical  plane  of  the  large 
telescope  and  to  a  horizontal  position  by  means  of  its  level.  The  two 
telescopes  will  then  form  an  angle  which  equals  the  amount  of  the  decli- 
nation, and  the  inclination  of  the  solar  telescope  to  its  polar  axis  will 
be  equal  to  the  polar  distance  of  the  sun. 

Second.  Without  disturbing  the  relative  positions  of  the  two 
telescopes,  incline  them  and  set  the  vernier  to  the  co-latitude  of  the 
place. 

By  moving  the  transit  and  the  '  *  Solar  Attachment ' '  around  their 
respective  vertical  axis,  the  image  of  the  sun  will  be  brought  into  the 
field  of  the  solar  telescope,  and  after  accurately  bi- 
secting it  the  transit  telescope  must  be  in  the  meri- 
dian, and  the  compass-needle  indicates  its  deviation  at 
that  place. 

The  vertical  axis  of  the  "  Solar  Attachment " 
will  then  point  to  the  pole,  the  apparatus  being  in 
fact  a  small  equatorial. 

Time  and  azimuth  are  calculated  from  an  ob- 
served  altitude  of  the  sun  by  solving  the  spherical 
triangle  formed  by  the  sun,  the  pole,  and  the  zenith 
of  the  place.  The  three  sides,  S  P,  P  Z,  Z  S,  complements  respectively 
of  the  declination,  latitude,  and  altitude,  are  given,  and  we  hence  deduce 
S  P  Z,  the  hour  angle,  from  apparent  noon,  and  P  Z  S,  the  azimuth  of 
the  sun. 

The  "Solar  Attachment"  solves  the  same  spherical  triangle  by 
construction,  for  the  second  process  brings  the  vertical  axis  of  the  solar 
telescope  to  the  required  distance,  Z  P,  from  the  zenith,  while  the  first 
brings  it  to  the  required  distance,  S  P,  from  the  sun. 


Observation  for  Time. 


If  the  two  telescopes,  both  being  in  position-one  in  the  meri- 
dian, and  the  other  pointing  to  the  sun -are  now  turned 
horizontal  axis,  the  vertical  remaining  undisturbed,  until  each  » 


ILLUSTRATED   CATALOGUE   OF 


the  angle  between   their  directions  (found  by  sighting  on  a    distant 
object)  is  S  P  Z,  the  time  from  apparent  noon. 

This  gives  an  easy  observation  for  correction  of  time-piece,  reli- 
able to  within  a  tew  seconds. 


To  Obtain  the  Latitude  with  the  "  Saegmuller  Solar 

Attachment." 

L,evel  the  transit  carefully  and  point  the  telescope  toward  the 
south  and  elevate  or  depress  the  object  end,  according  as  the  declina- 
tion of  the  sun  is  south  or  north,  an  amount  equal  to  the  declination. 

Bring  the  solar  telescope  into  the  vertical  plane  of  the  main  tele- 
scope, level  it  carefully  and  clamp  it.  With  the  solar  telescope  observe 
the  sun  a  few  minutes  before  its  culmination  ;  bring  its  image  between 
the  two  horizontal  wires  by  moving  the  transit  telescope  in  altitude  and 
azimuth,  and  keep  it  so  by  the  slow  motion  screws  until  the  sun  ceases 
to  rise.  Then  take  the  reading  of  the  vertical  arc,  correct  for  re- 
fraction due  to  altitude  by  the  table  below.  Subtract  the  result  from 
90°,  and  the  remainder  is  the  latitude  sought. 

Mean  Refraction. 

Barometer  30  inches,  Fahrenheit  Thermometer  50°. 


Altitude. 

Refraction. 

1 

Altitude. 

Refraction. 

10° 

5'  19" 

20° 

2'  39" 

II 

4   5i 

25 

2     04 

12 

4    27 

30 

I     41 

13 

4   07 

35 

I      23 

14 

3    49 

40 

I     09 

15 

3    34 

45 

58 

16 

3    20 

50 

49 

17 

3    08 

60 

34 

18 

2    57 

70 

21 

19 

2     48 

80 

10 

The  following  table,  computed  by  Prof.  Johnson,  C.  E.,  Wash- 
ington University,  St.  L/ouis,  will  be  found  of  considerable  value  in 
solar  compass  work: 


J.    C.    SALA,    SAN    FRANCISCO 


"  This  table  is  valuable  in  indicating  the  errors  to  which  the  work  is  liable 
at  different  hours  of  the  day  and  for  different  latitudes,  as  well  as  serving  to  cor- 
rect the  observed  bearings  of  lines  when  it  afterwards  appears  that  a  wrong  lati- 
tude or  declination  has  been  used.  Thus  on  the  first  day's  observations  I  used  a 
latitude  in  the  forenoon  of  38°  37',  but  when  I  came  to  make  the  meridian  obser- 
vation for  latitude  I  found  the  instrument  gave  38°  39'.  This  was  the  latitude 
that  should  have  been  used,  so  I  corrected  the  morning's  observations  for  two 
minutes  error  in  latitude  by  this  table. 

"It  is  evident  that  if  the  instrument  is  out  of  adjustment  the  latitude 
found  by  a  meridian  observation  will  be  in  error;  but  if  this  observed  latitude 
be  used  in  setting  off  the  co-latitude  the  instrumental  error  is  eliminated.  There- 
fore always  use  for  the  co-latitude  that  given  by  the  instrument  itself  in  a  meri- 
dian observation." 


Errors  in  Azimuth  (by  Solar  Compass)  for  i  mm.  Error 
in  Declination  or  Latitude. 


HOUR. 

FOR  i  MIN.  ERROR  IN 
DECLINATION. 

FOR  i  MIN.  ERROR  IN 
LATITUDE. 

Lat.  30° 

Lat.  40° 

Lat.  50° 

Lat.  30° 

Lat.  40° 

Lat.  50° 

II.  30  A.M.   ) 
12.  30  P.M.   \ 

MIN. 

8.85 

MIN. 
10.00 

MIN. 
I2.9O 

MIN. 

8.77 

MIN. 
9.92 

MIN. 
11.80 

I  1.  00  A.M.   \ 
1.  00  P.M.   i 

4.46 

5-05 

6.01 

4-33 

4.87 

5.80 

IO.OOA.M.   / 
2.00  P.M.    ( 

2.31 

2.6l 

3-H 

2.00 

2.26 

2.70 

Q.OOA.M.    ) 
3.00  P.M.    ( 

1.63 

1.85 

2.20 

1.15 

1.30 

1.56 

8.00A.M.    J 
4.00  P.M.    j 

i-34 

«'•$« 

I.  80 

0.67 

0.75 

0.90 

7.  00  A.M.    / 
5.00  P.M.    \ 

1.20 

i-35 

1.61 

0.31 

0-35 

0-37 

6.00A.M.    / 
6.00  P.M.    $ 

I-I5 

1.30 

1.56 

o.oo 

o.oo 

O.OO 

NoT,-Azimuths  observed  with  erroneous  deduction  or  co 
rected  by  means  of  this  table  by  observing  that  for  tlv        e  of  co 
the  azimuth  of  any  line  from  Ike  south  point  ^  the  d.rec  ,on  S.  W.  N 
smalt  in  ^forenoon  and  too  large  in  the  "t'e™00  ar 

minute  of  error  in  the  altitude  of  the  line  of  si*ht.    T 


^  ^ 


too  low. 


n6 


ILLUSTRATED    CATALOGUE   OF 


Correction   for   Refraction. 

This  correction  is  applied  to  the  declination  of  the  sun,  and  is 
equal  to  the  refraction-correction  of  the  sun's  observed  altitude  multi- 
plied by  the  cosine  of  the  angle  which  the  sun  makes  between  the 
decimation -circle  and  the  vertical. 

In  order  to  reduce  the  refraction-correction  to  the  simplest  possible 
form,  we  have  added  a  separate  column  to  the  ephemeris  containing 
them,  which  we  publish  every  year.  They  are  thus  brought  in  imme- 
diate juxtaposition  with  the  decimation  angle,  and  we  think  the 
arrangement  will  be  appreciated  by  those  who  use  the  Solar  Attach- 
ment. 

Latitude  Coefficients. 


LAT. 

COEFF. 

LAT. 

COEFF. 

LAT. 

COEFF. 

LAT. 

COEFF. 

15° 

•30 

27° 

-56 

39° 

.96 

5i° 

•47 

16 

•32 

28 

•59 

40 

.00 

52 

•53 

*7 

•34 

29 

.62 

4i 

.04 

53 

•58 

18 

.36 

30 

•65 

42 

.08 

54 

.64 

19 

•38 

3i 

.68 

43 

.12 

55 

.70 

20 

.40 

32 

•7i 

44 

.16 

56 

.76 

21 

.42 

33 

•75 

45 

.20 

57 

.82 

22 

•44 

34 

.78 

46 

.24 

58 

.88 

23 

.46 

35   . 

.82 

47 

.29 

59 

•94 

24 

.48 

36 

•85 

48 

•33 

60 

2.00 

25 

•50 

37 

•89 

49 

1.38 

26 

•53 

38 

•92 

50 

1.42 

J.    C.    SALA,    SAN   FRANCISCO 


Refraction   Correction,   Lat.  40°. 


January.  • 

February. 

March. 

April. 

May. 

Juue. 

1 
2 

lh.1  58 
2  2  16 
3  3  04 

1 

2 

1 

2 

lh  1  03 
2  1  10 

3  1  27 

1 
3 

3h  0  57 
4  i  19 
5  2  18 

1 
2 

lh.0  28 
2  0  32 
3  0  39 

1 
2 

5li  I  11 

3 
4 

4  6  23 
1  1  54 

3 
4 

lh.1  26 
2  I  37 

3 
4 

4  2  06 
5  4  39  1   * 

1  0  39 

2  0  44 

3 

4  0  55 
5  1  30 

3 
4 
5 

1  0  19 
2  0  23 
3  0  30 

5 

2  2  11 

5 

3  2  04 

5 

1  0  59     6 

3  0  54 

4 

1  0  26 

6 

4  0  43 

6 
7 

3  2  59 

7 

4  3  21 

6 

7 

2  I  06 
3  1  21 

7 
8 

4  I  14 
5  2  06 

5 

6 

2  0  30 
3  0  37 

7 

5  I  10 

8 

9 
10 
11 
12 
13 

4  6  01 
1  I  51 
2  2  07 
3  2  51 
4  5  40 

8 
9 
10 
11 
12 

1  1  21 
2  1  31 
3  1  56 
4  3  04 

8 
9 

10 
11 
12 

4  1  56 
5  4  04 

1  0  55 
2  I  02 
3  1  15 

9 
10 
11 
12 
•  13 

'  1  0  36 
2  0  41 
3  0  51 
4  1  10 
5  1  58 

7 

9 
10 
11 

12 

4  0  53 
5  1  26 
1  0  25 
2  0  29 
3  0  36 
4  0  51 

8 
9 
10 
11 
12 

13 

I  0  IS 
2  0  22 
3  0  29 
4  0  43 

5  1  09 

1  0  18 

14 

1  1  46 

13 
14 

1  1  16 
2  1  25 

13 
14 

4  I  47 
5  3  34 

14 
15 

1  0  34 
2  0  38 

13 
14 

5  1  22 
1  0  23 

14 
15 

2  0  22 
3  0  29 

15 
16 
17 
18 

19 
20 
21 
22 
23 

24 
25 

2  2  01 
3  2  40 
4  5  00 
1  1  42 
2  1  56 
3  2  31 
4  4  35 
1  1  37 
2  1  58 

15 
16 
17 

18 
19 
20 
21 
22 

23 

24 
25 

3  1  48 
4  2  47 
5  8  39 

1  1  12 
2  1  20 
3  1  40 
4  2  31 
5  6  49 

I  1  07 
2  1  15 
3  1  33 

15 
16 
17 
18 
19 

20 
21 
22 
23 
24 

1  052 
2  0  58 
3  1  10 
4  1  39 
5  3  08 

1  0  48 
2  0  54 
3  1  05 
4  132 
5  2  51 

16 
17 
18 

19 
20 
21 
22 
23 

24 
25 
26 

3  0  48 
4  1  06 
5  1  49 

1  0  32 
2  0  36 
3  0  45 
4  1  02 
5  1  42 

1  0  30 
2  0  34 
3  0  42 

15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 

2  0  27 
3  0  34 
4  0  49 
5  1  18 
1  0  22 
2  026 
3  0  33 
4  0  47 
5  1  15 
1  0  21 
2  0  25 
3  0  32 

16 
17 

18 
19 
20 
21 
22 

23 
24 
25 
26 

4  0  42 

5  .  1  08 

1  0  18 
2  0  22 
3  0  28 
4  0  42 
5  1  08 

1  0  18 
2  0  22 
3  0  29 
4  0  42 

2« 

26 

4  2  18    25 

1  0  45 

27 

4  0  58  !  27 

4  0  40 

27 

5  1  08 

27 

3  2  22 

27 

5h.5  28    26 

2  0  50    28 

5  1  36    28 

5  1  13 

28 
29 

4  4  07 
1  1  32 

28 

27 

28 

3  1  01 
4  1  25 

29 
30 

1  0  28  1  29    1  0  20 
2h  0  32       i  2  0  24 

28 
29 

1  0  18 
2  0  22 
3  0  29 

30 

2  1  44 

'ft 

5  2  34 

30    3  0  31 

30    4h.O  43 

3  -2  13 

30 

1  0  42 

4  0  44 

31 

4h.3  41 

31 

2h.O  47 

31 

5h.l  11 

July 

August. 

September. 

October. 

November. 

December. 

5h.l  09 

1 

1 

lh.0  39 

1 

lh.0  59 

1    2h.3  21 

1    lh  1  54 

2 

2  0  44 

2 

2  1  06 

2 

3  13  57 

9    2  2  11 

1  0  19 
2  0  23 
3  0  3<> 

2 
3 
4 

lh  0  26 
2  0  30 
3  0  37 

3 
4 
5 

3  0  54 
4  1  14 
5  2  08 

3 

J 

4  1  56 
5  4  04 

3 
4 

5 

4 
5 

1  1  32 

:  3  259 

3    4  6  01 

4  |  5 

4  0  43 

5 

4  0  53     f> 

1  0  42 

6    I  1  03 

6 

2  i  44 

5    1  1  58 

5  1  10 

6 

5  1  26  i   7 

2  0  47 

7    2  1  10 

7 

3  2  13 

6    2  2  16 

1  0  20 

7  j  1  028     ^ 

3  0  57 
4  1  19 

8 
9 

3  1  27 

4  2  or, 

8 
9 

4  3  41 
5 

7 
8 

3  3  04 
4  6  23 

2  0  24 
3  0  31 
4  0  44 
5  1  11 

1  0  21 
2  0  25 
3  0  32 
4  0  46 
5  1  13 

1  0  22 
2  0  26 
3  0  33 
4  0  47 
5  1  15 

1  0  23 
2  0  27 
3  0  34 
4  0  49 
5  1  18 

1  0  25  ' 
2  0  29 
3  0  36 

8 
9 
10 
11 

12 
13 
14 
15 
16 

17 
18 
19 
20 
21 

22 
23 
24 
25 
26 

27 
28 
29 

2  0  32 
3  0  39 
4  0  55 
5  1  30 

1  0  30 
2  0  34 
3  0  42 
4  0  58 
5  1  36 

1  0  32 
2  0  36 
3  0  45 
4  1  02 
5  1  42 

1  0  34 

2  0  38 
3  0  48 
4  1  06 
5  1  49 

1  0  36 
2  0  41 
3  0  51 

10 
11 
12 
13 
14 
15 

16 
17 
18 
19 
''O 

21 
22 
23 
24 
25 

26 
27 
28 
29 
30 

5  2  18 

1  0  45 
2  0  50 
3  1  01 
4  '1  25 
5  2  34 

1  0  48 
2  0  54 
3  105 
4  1  32 
5  2  51 

1  0  52 
2  0  58 
3  1  10 
4  1  39 
5  3  08 

1  0  55 
2  1  02 
3  1  15 
4  I  47 
5h.3  34 

10 
11 
12 
13 
14 
15 

16 
17 
18 
19 
20 

21 
22 
23 
24 
25 

26 
27 
28 
29 
30 

5  4  39 

1  1  07 
2  1  15 
3  1  33 
4  2  18 
5  5  39 

1  1  12 
2  1  20 
3  1  40 
4  2  31 
5  6  29 

1  1  16 
2  1  25 
3  1  48 
4  2  47 
5  8  39 

1  1  21 
2  1  31 
3  1  56 
4  3  04 
5  11  01 
lh.1  26 

10 
11 
12 
13 
14 

15 
16 

17 
18 
19 

20 
21 
22 
23 
24 

25 
26 
27 
28 
29 

30 

M 

1  1  37 
2  150 
3  2  22 
4  4  07 
5 

1  1  42 
2  1  56 
3  2  31 
4  4  35 
5 

1  1  46 
2  2  01 
3  2  40 
4  4  59 
5 
1  1  50 
2  2  06 
3  2  49 
4  5  33 
5h. 

10 
11 
12 
13 
14 

15 

16 
17 
18 
19 

20 
21 
22 
23 
24 

25 
26 
27 
28 
29 

30 

5 

1  2  00 
2  2  19 
3  3  09 
4  6  38 
5 
1  2  01 
2  2  20 
3  3  11 
4  6  47 
5 

1  2  01 
2  2  20 
3  3  11 
4  6  49 
5 

1  2  00 

2  2  19 
3  3  09 
4  6  43 
5h. 

4  0  51 

30 

4  1  10 

31 

1  37 

11 

5h.l  22    31 

5h.l  58 

I 

2  04 

«M 

Il8  ILLUSTRATED    CATALOGUE   OF 


The   Preparation   of  the    Declination    Settings  for   a 

Day's    Work. 

The  Solar  Ephemeris  gives  the  declination  of  the  sun  for  the 
given  day,  for  Greenwich  mean  noon.  Since  all  points  in  America  are 
west  of  Greenwich,  by  5,  6,  7,  or  8  hours,  the  declination  found  in  the 
ephemeris  is  the  declination  at  the  given  place  at  7,  6,  5,  or  4  o'clock 
A.  M.,  of  the  same  date,  according  as  the  place  lies  in  the  "Eastern," 
''Central,"  "  Mountain,"  or  "  Western  Time  "  belts  respectively. 

The  column  headed  ' '  Refraction  Correction  ' '  gives  the  cor- 
rection to  be  made  to  the  declination,  for  refraction,  for  any  point  whose 
latitude  is  40°.  If  the  latitude  is  more  or  less  than  40°  these  cor- 
rections are  to  be  multiplied  by  the  corresponding  coefficients  given  in 
the  table  of  "Latitude  Coefficients,"  p.  116.  Thus  the  refraction  cor- 
rections in  latitude  30°  are  65  hundredths,  and  those  of  50°  142  hun- 
dredths  of  the  corresponding  ones  in  latitude  40°.  There  is  a  slight 
error  in  the  use  of  these  latitude  coefficients,  but  the  maximum  error  will 
not  amount  to  over  15",  except  when  the  sun  is  very  near  the  horizon, 
and  then  any  refraction  becomes  very  uncertain.  All  refraction  tables 
are  made  out  for  the  mean,  or  average,  refraction,  whereas  the  actual 
refraction  at  any  particular  time  and  place  may  not  be  more  than  one- 
half,  or  as  much  as  twice  the  mean  refraction,  with  small  altitudes.  The 
errors  made  in  the  use  of  these  latitude  coefficients  are,  therefore,  very 
small  as  compared  with  the  errors  resulting  from  the  use  of  the  mean, 
rather  than  unknown  actual  refraction  which  affects  any  given 
observation. 

Example  I. 

Let  it  be  required  to  prepare  a  table  of  declinations  for  a  point 
whose  latitude  is  38°  30',  and  which  lies  in  the  "  Central  Time  "  belt, 
for  April  5,  1890. 

Since  the  time  is  6  hours  earlier  than  that  at  Greenwich,  the 
declination  given  in  the  ephemeris  is  the  declination  here  at  6  A.  M.  of 
same  date.  This  is  found  to  be  +  6°  9;  57/;.  To  this  must  be  added 


J.    C.    SALA,    SAN   FRANCISCO 


the  hourly  change,  which  is  also  plus,  and  equal  to  56 ".83.     The  lati- 
tude coefficient  is  0.94.     The  following  table  may  now  be  made  out : 

Declination  Settings  for  April  5,  1830,  Lat.  j<?°  jo'\   Central   Time. 


Hr. 

Declination 

Ref.  Cor. 

Setting. 

Hr. 

Declination 

Ref.  Cor. 

Setting. 

7 

+  6°  10/54" 

+    2'  007/ 

6°  1  2  '54" 

I 

6°i6/35// 

+     377/ 

6oi7'i2" 

8 

6    II    51 

I     IO 

6   13  01 

2 

6   17  31 

4i 

6    18  12 

9 

6   12  47 

51 

6   1338 

3 

6   18  28  !        51 

6   19  19 

10 

6   13  44 

41 

6   14  25 

4 

6   19  25 

I     IO 

6  20  35 

ii 

6   14  41 

37       6  15  18 

5 

6    20    22 

2    OO 

6    22   22 

Example  II. 

Let  it  be  required  to  prepare  a  declination  table  for  a  point  in  lat- 
itude 45°,  in  the  "  Eastern  Time  "  belt,  for  Oct.  10,  1890. 

The  time  now  is  5  hours  earlier  than  that  of  Greenwich,  hence 
the  declination  given  in  the  ephemeris  for  Greenwich  mean  noon  is  the 
declination  at  our  point  at  7  A.  M.  The  declination  found  is— 6°  43' 
.-)<;  ',  and  the  hourly  change  is— 56'.87.  The  latitude  coefficient  is  1.20. 

The  table  then  becomes  : 

Declination  Setting  for  Oct.  10,  1890,  Lat.  45°,  Eastern  Time. 


Hr. 

Dec  1  in  ation 

Ref.  Cor. 

Settings. 

Hr. 

Declination 

Ref.  Cor. 

Settings. 

7 

-6°43'56" 

+  5'  35" 

-6°38'2l" 

I 

-6°49/37// 

+  i'  16" 

-6°  48  '21" 

8 

6  44  53 

2    31 

6    42   22 

2 

6  5034 

i   24 

6  49  10 

9 

10 

ii 

6  45  50 
6  46  47 
6  47  44 

i  44 

i   24 
i    16 

6  44  06 

6  45  23 
6  46  28 

3 

4 
5 

6  51  3' 

6  52  28 

6  53  25 

i  44 
2  31 

5  35 

6  49  47 

6  49  57 
6  47  50 

If  the  date  be  between  June  20  and  Sept.  20  the  declination  is 
positive  and  the  hourly  change  negative,  while  if  it  be  between  Dec.  20 
and  March  20  the  declination  is  negative  and  the  hourly  change  posi- 
tive. The  refraction  correction  is  always  positive  ;  that  is,  it  always 
increases  numerically  the  north  declinations  and  diminishes  numeri- 
cally the  south  declinations.  The  hourly  refraction  corrections  giver 
in  the  ephemeris  are  exact  for  the  middle  day  of  the  five-day  pen 
corresponding  to  that  set  of  hourly  corrections.  For  the  extreme  days 


120  ILLUSTRATED   CATALOGUE   OF 


of  any  such  period  an  interpolation  can  be  made  between  the  adjacent 
hourly  corrections,  if  desired. 

By  using  standard  time  instead  of  local  time  a  slight  error  is 
made,  but  the  maximum  value  of  this  error  is  found  at  those  points 
where  the  standard  time  differs  from  the  local  time  by  one-half  hour, 
and  in  the  spring  and  fall  when  the  declination  is  changing  rapidly. 
The  greatest  error,  then,  is  less  than  30 ",  and  this  is  smaller  than  can 
be  set  off  on  the  vertical  circle  or  declination  arc.  Even  this  error  can 
be  avoided  by  using  the  true  difference  of  time  from  Greenwich  in 
place  of  the  standard  meridian  time. 


TOPOGRAPHICAL     SURVEYING 


-   BY   - 


ERNEST    McCULLOUGH,  C.   E. 


I.     SURVEYING  BY  CAMERA. 
II.     STADIA  SURVEYING. 


I.     Surveying    by    Camera.* 

The  principle  depends  upon  the  art  of  projecting  perspective 
views  upon  a  horizontal  plane. 

Any  camera  may  be  used  provided  it  is  perfectly  level  when  the 
view  is  taken,  and  the  smallest  size  adapted  for  the  work  is  one  with  a 
5 X  8-inch  plate.  Although  an  ordinary  camera  may  be  used,  it  is 
better  to  have  one  for  the  purpose,  provided  with  two  levels  and  four 
leveling  screws.  The  box  should  be  solid,  and  focusing  done  by  means 


^Written  in  1891  and  revised  in  1896  for  this  manual. 


J.    C.    SAI,A,    SAN    FRANCISCO 


121 


of  the  objective  slide.  If  the  camera  has  a  compass,  or  a  horizontal 
limb  and  a  vertical  limb,  it  will  be  complete. 

Glass  negatives  are  the  most  accurate  to  use,  but  paper  negatives 
on  account  of  portability  are  more  convenient. 

The  several  adjustments  of  the  camera  must  not  be  neglected. 
The  first  is  called  "the  test  for  register."  The  film  on  the  sensitive 
plate  must  exactly  replace  the  surface  of  the  ground  glass.  To  do  this 
set  the  instrument  up  and  focus  for  a  distant  view.  Make  a  scratch  to 
show  the  relative  positions  of  the  plate  and  tube.  Take  out  the  ground 
glass,  and  put  in  one  with  a  transparent  film.  Focus  on  this,  and  make 


Fig.i 


another  mark.  In  actual  work  this  difference  must  be  allowed  for  by 
changing  the  focus  after  the  removal  of  the  ground  glass,  so  the  film 
on  the  plate  will  be  in  the  right  position.  The  instrument  maker 
should  see  to  the  register. 

The  focal  distance  must  be  accurately  determined.     Lens  makers 
usually  state  the  focal  distance,  but  as  it  is  liable  to  vary,  the  operator 
had  better  determine  it  himself.     For  simple  convex  lens,  double  or 
piano  convex   lens,  measure  from  optic  center  to  surface  , 
glass.     For  double  compound  lenses  proceed  as  follows:     (Fig.  1.) 

Set  up  several  stakes  in  the  ground  distant  from  0  about  two  or 
three  hundred  feet,  as  5  S<  S"  S"'  S"".     With  transit  at  Q,  measure 


122  ILLUSTRATED    CATALOGUE   OF 


angles  ,5*  O  S",  etc.  Set  up  the  camera  at  O,  level  it  carefully,  make 
the  image  S"  coincide  with  a  vertical  line  through  the  center  of  the 
plate,  and  photograph  the  stakes.  The  greater  the  distance  apart  on 
the  plate  of  the  stakes,  the  more  accurate  will  be  the  determination  of 
the  focal  length.  G  G  represents  the  plate,  O  P  the  focal  length. 
Measure  s"  s""  on  plate,  then 


For  a  test  of  distortion  of  the  lens,  with  O  P  just  found,  compute 
the  angles  5  O  S1  S  O  S",  etc.,  and  if  they  agree  with  angles  taken 
with  the  transit  the  lens  is  free  from  distortion. 

Next,  the  horizon  of  the  view  must  be  found.  Find  the  center 
of  the  ground  glass  and  draw  a  vertical  and  horizontal  line  through  it. 
Level  the  instrument  carefully,  and  set  beside  it  an  engineer's  level, 
with  the  telescope  at  same  height  as  the  lens  of  the  camera.  With  the 
level  find  some  object  in  the  distance.  Turn  the  camera  to  this  object 
and  move  the  object  slide  up  and  down  until  the  object  is  exactly  at 
the  intersection  of  the  lines  on  the  ground  glass,  the  object  slide  is 
then  in  its  normal  position,  and  a  scratch  on  the  slide  will  determine 
that  position  for  all  time.  This  .scratch  should  be  marked  zero,  and 
graduations  should  extend  above  and  below  it.  The  lower  graduations 
should  have  a  minus  sign  before  their  numbers.  The  plate  holder 
should  have  four  fine  needles  so  inserted  in  the  frame  that  their  shadows 
will  be  photographed.  When  the  picture  is  developed,  lines  scratched 
on  the  plate  and  connecting  these  points  will  occupy  the  same  positions 
as  the  lines  drawn  on  the  ground  glass. 

The  horizontal  line  represents  the  horizon  of  the  picture,  and  is 
the  trace  of  a  line  on  a  level  with  the  center  of  the  instrument.  The 
object  of  graduating  the  vertical  movement  of  the  object  slide  is  to 
provide  for  a  changing  of  the  horizon  when  necessary  to  limit  sky  views. 
By  noting  the  number  on  this  index  when  the  view  is  taken,  the  actual 
horizon  of  the  picture  is  set  off  from  the  horizon  of  the  instrument 
when  plotting. 

To  measure  the  field  of  view,  half  the  length  of  the  plate  divided 
by  the  focal  length  gives  the  tangent  of  half  the  horizontal  angle.  The 


J.  c.  SALA,  SAN  FRANCISCO 


123 


horizontal  angle  is  the  field  of  view,  and  dividing  360°  by  this  angle, 
gives  the  number  of  views  needed  to  go  around  the  circle. 

Half  the  width  of  the  plate,  divided  by  the  focal  length,  gives 
the  tangent  of  half  the  vertical  angle.  As  a  general  proposition  it  may 
be  stated  that  the  greater  the  focal  length,  the  smaller  the  field  of  view 
and  the  greater  the  accuracy  in  the  work.  The  smaller  the  focal 
length,  the  greater  the  field  of  view,  greater  rapidity  (because  fewer 
views)  and  less  accuracy. 

Set  up  the  camera  and  level  it  carefully.  Adjust  to  focal  length 
and  set  object  slide  to  most  favorable  position  and  note  index  number 
for  fixing  horizon.  Adjust  stop,  set  the  plate  holder  and  verify  the 
leveling.  The  levels  are  apt  to  get  a  little  out  during  all  the  handling. 
When  all  is  ready  take  the  picture.  The  camera  must  be  rigid  and  the 
plate  truly  vertical. 


The  Plotting. 

On  the  plate  draw  the  horizontal  line  (the  horizon)  and  the  ver- 
tical line,  from  the  shadows  of  the  points  of  the  needles.  If  the 
objective  was  above  or  below  the  horizon,  then  instead  of  drawing  it 
draw  a  line  parallel  to  it  above  or  below,  as  indicated  by  the  index 
number  observed.  From  the  vertical  line  measure  to  the  right  or  left 
to  the  object  you  wish  to  locate,  and  divide  this  distance  by  the  focal 
length,  this  will  give  the  tangent  of  the  horizontal  angle  from  the  line 
of  sight.  From  the  horizontal  line,  which  is  a  trace  of  the  plane  of 
the  optic  center,  measure  up  or  down,  as  the  case  may  be,  to  the  object, 
and  divide  this  distance  by  the  focal  length  to  obtain  the  tangent  of  the 
vertical  angle. 

Every  point  located  on  the  map  must  show  in  at  least  two  views. 
These  views  are  taken  from  points  previously  fixed  by  triangulation  or 
by  direct  measurement.  The  points  from  which  the  views  are  taken 
must  be  plotted,  and  from  these  points  lines  drawn  on  the  bearings 
given  in  the  field  notes  when  the  view  was  taken.  On  these  bearings 
lav  off  the  focal  distance,  and  at  the  end  of  this  line  draw  one  at  right 
angles  to  represent  the  plate.  On  the  line  representing  the  plate,  lay 


124  ILLUSTRATED    CATALOGUE   OF 

off  on  either  side  the  distances  from  the  vertical  to  the  object,  and  from 
the  point  of  view  draw  lines  through  these  points.  The  lines  through 
two  plates  produced  to  an  intersection  locate  the  objects. 

Figure  2  illustrates  the  method  of  plotting.  O  O1  represent  the 
points  from  which  the  views  were  taken.  G  G1  and  G11  G1"  the  plates, 
O  P  and  O1  P1  the  line  of  direction  of  sight.  ABC  etc.  and  A1  B1  O 
etc.  represent  on  the  plate  the  objects  to  be  located  and  their  positions 
on  the  maps  are  shown  by  the  points  of  intersection. 

To  fix  the  elevation,  measure  the  distance  from  point  of  sight  to 
object,  and  multiply  into  tangent  of  vertical  angle  already  found;  add 
to  the  elevation  of  the  point  from  which  the  sight  was  taken,  the 


height  of  instrument,  and  add  or  subtract,  according  to  whether  the 
point  is  above  or  below  the  horizon,  the  height  above  ascertained. 
This  will  give  the  elevation  of  the  object  above  datum. 

Spherical  aberration  does  not  interfere  with  the  accuracy  of  the 
work,  provided  the  focal  length  is  ascertained  by  means  of  a  point  near 
the  extremity  of  the  plate  in  the  horizon.  (See  Fig.  1.) 


Field  Work. 

1.  The  ground  may  be  triangulated  with  the  transit  and  views 
taken  from  the  triangulation  points  with  the  camera,  the  direction  of 
the  views  to  be  ascertained  by  azimuths  from  the  lines  between  stations. 
These  azimuths  to  be  taken  by  a  compass,  or  by  means  of  a  horizontal 
limb. 


J.    C.    SALA,    SAN    FRANCISCO 


125 


The  camera  may  be  used  in  connection  with  a  pocket  com- 
pass, the  work  starting  from  a  measured  base. 

3.  The  work  may  be  done  *ith  a  camera  alone,  fitted  with  a 
compass,  horizontal  limb  and  vertical  circle.  In  this  case  the  triangu- 
lation  is  carried  on  with  the  work. 

Below  is  a  form  of  record. 


Station. 

View. 

Remarks. 

Number. 

Index  No. 

Bearing. 

A  

i 

T  n  c  i/  ° 

2 

o 

I95/2 

227° 

B  

8/1° 

°4 

The  index  number  may  be  the  same  or  different  for  all  views  at 
the  same  station.  Any  time  of  the  year  is  good  for  this  work,  and  any 
hour  of  the  day  when  the  air  is  clear.  Long  distances  between  stations 
should  be  chosen,  as  short  bases  increase  error.  A  few  views  only  are 
necessary,  as  sketches  may  be  made  of  unimportant  places,  and  these 
views  should  be  well  chosen.  A  little  care  exercised  in  selecting  posi- 
tions will  save  much  office  work. 


Office    Work. 

Upon  the  scale  used  depends  the  accuracy  of  the  plotting.  If  the 
scale  is  large,  then  very  long  sights  should  not  be  attempted,  but  if  the 
scale  is  small,  then  of  course  the  range  can  be  longer.  The  error  in 
height  is  in  proportion  to  the  distance. 

When  the  plates  are  prepared  for  plotting,  tto  Pffce  notes  are 
placed  in  a  book  in  seven  columns  as  follows: 


126 


ILLUSTRATED    CATALOGUE   OF 


Form  of  Record  to  Reduce  Ht.  to  Common  Datum. 


View. 

Distance. 

Point. 

Ref.  ft. 

Va. 

I 

+  IO2 

2 

+    90 

3 

~    25 

Ref.  of 
Sta.  ft. 

True  Kiev, 
ft. 

Remarks. 

+460 

+562 

550 

435 

The  first  column  is  for  the  views. 

The  second  column  contains  the  distances  to  the  points. 

The  third  column  the  names  or  numbers  of  the  points. 

The  fourth  column  the  height  above  or  below  station. 

The  fifth  column  elevation  of  station. 

The  sixth  column  elevation  of  point. 

The  seventh  column  for  remarks. 

For  drawing  in  contours,  the  fixing  of  natural  and  artificial  objects 
on  the  plan,  with  their  heights  noted,  will  give  all  the  data  necessary, 
together  with  a  close  inspection  of  the  proofs  as  the  work  proceeds. 
In  the  case  of  a  bare  country,  with  no  buildings,  fences  or  trees,  a  few 
painted  stakes  or  flags  put  in  at  salient  points  will  serve. 

It  is  best  to  work  directly  from  the  negatives,  as  the  paper  posi- 
tives are  too  much  affected  by  atmospheric  changes.  Blue  prints  are  as 
easy  to  work  from  as  silver  prints  if  positives  are  used. 


II.     Stadia    Surveying. 

A  stadia  survey  consists  of  three  operations: 

1.  The   triangulation,  or   fixing   of  points   to   base   the   stadia 
work  upon. 

2.  The  leveling  for  benchmarks. 

3.  The  stadia  work. 

The  stadia  work  proper,  is  merely  the  filling  in  work  of  the 
topographical  survey,  and  depends  for  its  accuracy  upon  the  care  with 
which  the  triangulation  has  been  done  and  the  benchmarks  fixed. 


J.    C.    SALA,    SAN   FRANCISCO 


In  surveying,  a  stadia  line  is  run  from  one  fixed  point  to  another 
and  all  errors  distributed  on  that  line  between  those  two  points,  so  that 
if  there  are  many  points,  the  total  c-ror  may  be  brought  within  very 
close  limits.  Whenever  a  benchmark  is  met,  a  reading  is  taken  on  it 
and  errors  in  elevation  distributed  between  adjacent  benchmarks. 

The  fixed  points  may  be  located  by  triangulation  or  by  any 
method  the  surveyor  prefers  so  that  enough  points  are  taken  and 
accurately  determined.  They  should  occupy  elevated  sites,  and  from 
any  one  a  clear  sight  should  be  had  to  two  others.  Each  point  can 
also  be  a  benchmark,  but  in  running  levels  from  one  to  the  other,  a 
number  of  other  points  can  have  their  elevation  determined  and  be 
properly  marked. 

The  instrument  is  set  on  one  of  the  fixed  points  and  a  sight  taken 
to  another  with  the  plate  clamped  at  zero  or  at  the  azimuth  of  that  line, 
the  azimuth  being  reckoned  from  true  north.  All  readings  are  taken 
from  0  to  360,  instead  of  "right"  and  "left."  The  angles  are  not 
double-centered  or  repeated,  and  the  telescope  is  not  reversed  on  any 
sights. 

One  or  more  rodmen  may  be  employed.  The  instrument  being 
oriented,  the  rodmen  go  to  the  points  to  be  located  and  also  hold  at 
each  change  of  slope,  the  rods  being  held  vertical.  The  instrument 
man  measures  the  height  of  the  telescope  center  above  the  ground  at 
the  station,  and  directs  the  middle  wire  to  that  reading  on  the  rod.  He 
then  takes  and  records  his  readings,  which  are: 

1.     The  horizontal  angle. 

'1.     The  vertical  angle.     (Plus  or  minus.) 

3.     The  readings  on  the  upper  and  lower  wire. 

The  readings  are  recorded,  each  in  its  proper  column  in  the  order 
set  forth,  but  in  practice  the  rod  readings  may  be  first  set  down  and  as 
the  instrument  is  clamped,  the  angles  may  be  read  while  the  rodman  is 
moving  to  a  new  position. 

When  all  the  sights  which  can  be  taken  from  one  point  are  taken, 
the  right  hand  rodman  is  motioned  forward  and  he  proceeds  to  selecl 
point  favorably  situated  for  sights.     The  left  hand  rodman  c 
the  instrument. 


128  ILLUSTRATED   CATALOGUE   OF 


The  point  selected  and  the  readings  taken,  tr^e  instrument  is 
moved  forward,  the  left  hand,  or  "rear"  rodman  holding  his  rod  on 
the  peg  just  left.  The  instrument  being  set  up,  vernier  "  B  "  is  set  to 
the  reading  last  taken,  so  that  vernier  "A"  reads  180°  different.  The 
telescope  is  directed  to  the  rear  rod  and  the  readings  taken.  This 
affords  a  check  on  the  forward  reading  and  should  never  be  neglected. 
The  rod  reading  should  be  the  same  as  previously  and  the  angle  should 
be  the  same  with  different  sign. 

The  rodmen  again  hold  their  rods  where  necessary,  and  the  former 
operations  are  repeated. 

When  a  fixed  point  is  arrived  at,  a  new  start  is  taken  from  it  so 
that  each  stadia  line  is  thus  independent  of  any  other. 


The    Triangulation. 

Sometimes  the  triangulation  may  be  carried  forward  with  the 
survey  by  a  method  akin  to  the  ''three-point  problem,"  where  three 
well  located  points  may  be  sighted  to  from  each  instrument  station  or, 
as  in  a  river  survey  or  preliminary  survey  for  an  irrigating  ditch  line, 
a  line  of  stakes  may  be  set  parallel  to  the  stadia  line  and  distant  several 
hundred  feet.  Bach  of  these  points  are  sighted  from  two  stations,  and 
at  every  tenth  station  a  new  base  line  is  measured  with  a  tape.  The 
writer  has  used  this  plan  with  good  results.  The  calculations  of  the 
sides  of  the  triangles  are  checked  by  the  stadia  readings  and  errors  are 
distributed  between  base  lines.  An  article  describing  the  method  very 
fully  appeared  in  the  Engineering  News  Oct.  12th,  1893,  a  reprint  from 
the  transactions  of  "The  Hng.  Assoc.  of  the  South,"  of  a  paper  by 
W.  G.  Kirkpatrick,  C.  E. 


The    Leveling. 


The  leveling  cannot  be  dispensed  with.  Elevations  taken  by  ver- 
tical angles  are  not  as  reliable  as  spirit-leveling,  owing  to  the  many 
adjustments  and  to  the  fact  that  vertical  circles  seldom  read  less  than 
minutes.  A  man  is  more  liable  also  to  misread  an  angle  than  a  rod. 


J.    C.    SALA,    SAN    FRANCISCO  I2g 


Having  frequent  points  at  which  to  stop  and  renew,  stadia  elevations 
introduces  an  element  of  certainty,  and  frequent  practice  will  show  to 
what  extent  the  vertical  angles  may  be  reliable. 


GENERAL     REMARKS. 

There  is  no  need  of  an  engineer  making  his  own  stadia  rods,  for 
if  the  wires  are  adjusted  to  read  one  foot  when  the  rod  is  one  hundred 
feet  distant,  (plus  constant)  an  ordinary  self-reading  leveling  rod  is 
sufficient. 

A  constant  must  be  added  to  all  sights,  as  the  rod  reading  is  not 
from  the  center  of  the  instrument  but  from  a  point  in  front  of  the 
telescope.  Measure  the  distance  from  the  center  of  the  telescope  to  the 
object  glass;  then  focus  on  a  distant  point  and  measure  the  distance 
from  the  stadia  wires  to  the  object  glass.  Add  the  twro  measurements 
together  and  the  result  is  a  constant  to  be  added  to  all  rod  readings. 

All  readings  are  to  be  reduced  to  the  horizontal,  so  it  is  not 
advisable  to  read  any  vertical  angles  greater  than  12°  on  the  line  or 
greater  than  20°  on  the  side  sights. 

Although  the  greater  the  length  of  sight,  the  greater  the  degree 
of  accuracy,  still  the  limiting  length  should  be  about  six  hundred  feet, 
except  in  rather  rough  work  on  account  of  atmospheric  conditions. 

Office    Work. 

As  a  result  of  the  field  operations,  four  columns  in  the  field  book 
have  been  filled  and  three  remain  to  be  filled  in  the  office. 
The  columns  are: 

1.  Horizontal  angles. 

2.  Vertical  angles.     (Plus  or  Minus.) 

3.  Reading  on  upper  wire. 

4.  Reading  on  lower  wire. 

5.  Bearings. 

6.  Distance  from  station. 

7.  Elevation  referred  to  datum. 


13°  ILLUSTRATED   CATALOGUE   OF 

No  sketches  are  necessary,  as  each  sight  is  described  on  the  page 
for  remarks. 

In  the  book  a  line  is  reserved  for  the  number  of  the  station,  the 
direction  to  the  fore  or  backsight,  and  its  elevation  referred  to  datum  if 
the  station  be  one  of  the  triangulation  points.  If  it  be  a  stadia  station 
the  line  tells  its  number  and  the  height  of  the  telescope  above  the 
ground.  Below  this  line  the  records  are  placed,  and  when  all  the 
sights  are  taken  from  one  point,  a  line  is  drawn  across  the  page  to 
separate  the  spaces  used  for  the  records  for  each  station.  Some  men 
use  a  page  for  each  station  but  no  useful  purpose  is  gained,  and  if  few 
sights  are  taken  much  space  is  wasted. 

The  following  formulas  should  be  used  for  reducing  stadia  read- 
ings on  the  line: 

d=  Ka  Cos2  n. 

e  =  Ka  y?,   Sin  in. 
n  =  Vertical  reading. 

k  =  A  constant  representing  the  wire  spacing  which  is  generally 
100. 

<2  =  The  reading  on  the  rod,  being  the  difference  between  the 
readings  on  the  upper  and  lower  wire,  plus  constant  added  to  all  rod 
readings. 

^=The  true  distance. 

e  —  Difference  in  elevation. 

By  these  formulas,  colums  6  and  7  can  be  filled  for  stations.  If 
the  horizontal  angles  were  azimuths  from  true  north,  column  5  can  be 
filled  for  all  readings. 

Columns  6  and  7  should  be  filled  by  formula  for  all  sights  on  the 
line.  That  is,  for  all  sights  which  carry  the  line  forward,  the  formula 
should  be  used  for  reduction  of  distance  and  elevation. 

For  side  sights  which  are  for  the  purpose  of  merely  obtaining 
contour  points,  the  columns  may  be  filled  from  diagram  readings. 

A  form  of  diagram  for  distances  is  illustrated  in  Fig.  1.  The 
vertical  line  at  the  end  is  divided  for  the  vertical  angles.  A  line  is  set 
off  perpendicularly  from  a  horizontal  line,  and  the  horizontal  line  may 
be  ten  or  twenty  inches  long.  In  the  diagram  it  is  supposed  to  be 
twenty  inches  long. 


J.    C.    SAI.A,    SAN    FRANCISCO 


GJ 


ILLUSTRATED   CATALOGUE   OF 


The  vertical  line  is  a  tangent  to  the  horizontal  line,  and  if  there 
was  no  correction  to  make  on  account  of  the  rod  being  held  vertical,  it 
would  be  sufficient  to  set  off  on  that  line  the  natural  tangent  of  the 
distance  for  whatever  angle  is  selected.  The  formula  for  distance  must 
however  be  used,  and  in  place  of  setting  off  on  the  vertical  line  the 
natural  tangent  of  the  distance  there  should  be  set  off  the  cos2. 

On  the  vertical  line  there  should  be  a  point  made  for  every  five 
minutes  of  angle.  For  instance  in  the  distance  two  hundred  and  for 
angle  five  minutes,  the  cos2  of  five  minutes  into  two  hundred  would 
give  the  distance,  on  the  vertical  line,  from  the  horizontal  on  which  a 
point  should  be  made. 

In  order  to  set  off  on  the  vertical  line  the  points  mentioned,  it  is 
necessary  to  describe  an  arc  of  a  circle  commencing  at  the  end  of  the 
horizontal  line,  with  center  at  A.  The  radius  of  the  circle  will  there- 
fore be  200. 

The  correct  distance  is  to  be  calculated  by  the  formula  and  set  off 
on  the  horizontal  line.  From  this  point  a  vertical  line  should  be  drawn 
to  intersect  the  arc.  Through  this  point  of  intersection  draw  the  lines 
from  A  to  the  vertical  line.  On  Fig.  1  an  arc  is  drawn  to  represent  the 
arc  mentioned.  It  does  not  have  to  be  inked  in  on  the  diagram. 

These  points  should  be  made  for  every  five  minutes  up  to  ten 

degrees,  and  from  ten  degrees  to  fifteen  for  each  ten  minutes.  From 

fifteen  to  twenty  degrees  the  angles  can   be  set  off  for  each  fifteen 
minutes  if  desired. 

Light  black  lines  can  connect  the  point  A  with  the  degree  marks 
and  light  red  lines  may  be  used  for  the  smaller  subdivisions. 

Fig.  No.  2  is  of  the  scale  for  obtaining  the  distances.  A  needle 
is  put  through  the  points  A  and  B,  and  the  scale  is  then  swung  around 
as  the  angle  is  called  off.  The  rod  reading  is  read  on  the  scale  and  the 
true  horizontal  reading  is  read  off  on  the  horizontal  line  at  the  bottom 
of  the  diagram.  For  example,  it  is  required  to  know  the  horizontal 
distance  for  a  rod  reading  of  175  feet  for  a  vertical  angle  of  ten  degrees 
and  four  minutes.  The  distance  scale  is  attached  and  laid  on  the  line 
leading  from  A  to  the  required  angle.  The  distance  of  175  feet  is  then 
read  on  the  scale  and  at  the  point  where  it  intersects  with  the  diagram 


J.    C.    SAL  A,    SAN    FRANCISCO 


133 


an  imaginary  vertical  line  is  dropped  to  the  base,  and  the  true  horizon- 
tal distance  is  then  read  off. 

It  is  convenient  to  divide  the  diagram  by  vertical  lines  one  inch 
apart  in  black,  and  divide  each  inch  into  tenths  in  red.     The  diagram 


I5o 


3o 


Distance     in    feeT 


3o< 


2 . 


it-OO 


300  <)00 


I5o 


feo 


being  twenty  inches  long,  it  follows  that  horizontal  distances  may  be 
read  to  the  nearest  foot  and  estimated  closer  for  readings  of  less  thai 
200  feet.  A  doubling  of  the  scale  will  secure  readings  of  two  feet  for 
rod  readings  of  less  than  400  feet,  etc.  The  accuracy  is  about  equal 
to  the  accuracy  of  the  rod  readings  themselves. 


134  ILLUSTRATED   CATALOGUE   OF 


The  paper  under  the  point  A  must  be  reinforced  with  cardboard 
or  strong  paper  to  prevent  the  needle  wearing  too  large  a  hole,  and  the 
scale  should  also  be  protected  where  the  needle  goes  through.  To 
insure  a  correct  setting  of  the  scale  there  should  be  a  vertical  line 
drawn  from  the  point  A,  and  when  the  scale  is  attached  for  work,  its 
edge  should  be  laid  along  the  two  rectangular  lines  starting  from  A. 
It  is  plain  to  see  that  when  the  readings  for  zero  and  ninety  degrees  are 
correct,  the  intermediate  readings  will  be  correct  if  the  hole  does  not 
wear  too  large.  The  vertical  and  horizontal  lines  are  graduated  the 
same  as  the  scale,  so  it  is  an  easy  matter  to  make  the  scale  coincide  both 
for  angle  and  distance. 

By  the  use  of  the  preceding  diagram,  all  distances  may  be  calcu- 
lated quickly.  One  man  can  call  off  the  angle  and  rod  reading,  and  the 
other  can  call  off  the  true  distance.  When  the  true  distances  are  all 
found,  the  differences  in  elevation  are  next  to  be  found.  For  this  pur- 
pose Fig.  2  is  used.  It  may  be  from  ten  to  twenty  inches  square.  In 
the  cut  it  is  supposed  to  be  fifteen  inches.  The  diagram  is  ruled  into 
one-inch  squares  and  each  square  into  tenths.  The  horizontal  lines  are 
the  true  distances  and  the  vertical  line  B-C  is  used  for  the  differences 
in  elevation.  It  will  be  noticed  that  one  foot  on  the  vertical  line  is 
equal  to  ten  feet  horizontally. 

On  the  vertical  line  the  angles  are  set  off  and  a  line  drawn  for 
each  five  minutes  for  every  degree  to  six,  and  for  each  ten  minutes  to 
ten  degrees,  after  which  the  interval  may  be  for  fifteen  minutes  or 
thirty,  at  the  option  of  the  man  using  the  scale.  To  obtain  the  differ- 
ence in  elevation  for  any  rod  reading,  the  angle  is  called  off  and  the 
line  followed  until  it  intersects  with  a  vertical  line  showing  the  true 
horizontal  distance.  This  point  will  show  the  difference  in  elevation 
between  the  instrument  and  the  point  where  the  rod  was  held.  On 
account  of  the  exaggeration  in  scale,  it  may  be  seen  that  close  readings 
are  possible. 

A  diagram  may  be  made  which  is  a  combination  of  the  two 
described,  and  which  will  give  the  distance  and  difference  in  elevation 
at  the  same  time.  To  construct  it  there  must  first  be  drawn  a  diagram 
for  calculating  elevations.  The  true  distance  should  be  calculated  for 
each  degree  and  for  each  one  hundred  feet  (counting  one  inch  on  the 


J.    C.    SALA,    SAN    FRANCISCO 


' 

136  ILLUSTRATED   CATALOGUE   OF 

^ ; _ 

horizontal  line  as  one  hundred  feet).  The  true  distances  should  thei] 
be  laid  off  on  the  lines  connecting  point  A  (Fig.  2)  with  the  degrees, 

There  will  then  be  on  all  the  lines,  points  about  one  inch  apart. 
Commencing  at  the  first  inch  on  the  bottom  line,  a  spline  can  be  benl 
to  connect  all  the  points  which  show  the  distance  for  a  rod  reading  oj 
100  feet  on  all  the  angles.  A  line  can  then  be  drawn  connecting  these 
points.  The  same  process  can  be  followed  at  200,  300,  etc.  The 
result  will  be  curved  lines  starting  from  the  points  on  the  lower  hori- 
zontal line  and  the  divisions  can  be  as  close  as  the  maker  of  the  dia- 
gram likes. 

It  being  desired  to  know  the  true  distance  and  difference  of  eleva- 
tion for  a  certain  rod  reading,  it  is  only  necessary  to  place  the  pencil  on 
the  bottom  horizontal  line  at  the  distance  given  in  the  rod  reading  and 
follow  the  curved  line,  which  begins  at  that  point,  until  it  intersects 
the  given  angle.  The  horizontal  line  at  that  point  gives  the  distance 
and  the  vertical  line  at  that  point  gives  the  difference  of  elevation. 

Edward  P.  Adams,  C.  K.,  described  two  excellent  stadia  charts 
in  the  May  1893  number  of  the  journal  of  the  Association  of  Engineer- 
ing Societies.  Any  engineer  can  make  them  and  they  do  not  depend 
upon  scaling  for  accuracy.  The  charts  themselves  need  to  be  accur- 
ately made,  but  once  made  the  scale  of  the  chart  cuts  no  figure. 


Plotting. 

When  all  the  readings  have  been  reduced  and  the  columns  in  the 
field  book  properly  filled,  the  plotting  is  commenced. 

First  all  the  triangulation  points  are  plotted  and  then  the  stadia 
lines  connecting  the  points.  These  stadia  lines  are  adjusted  for  errors, 
if  any,  and  then  the  work  of  plotting  the  side  sights  begins. 

To  adjust  the  errors  in  the  stadia  lines  the  following  is  a  good 
practical  method:  Plot  the  lines  and  if  they  do  not  meet  the  point 
properly,  scale  the  distance  by  which  they  strike  to  one  side  or  the 
other  and  divide  it  by  the  total  distance  to  find  the  natural  tangent  of 
the  amount  of  change  in  the  meridian  which  must  be  made  to  plot  in 
the  side  sights  correctly.  For  instance,  if  the  angle  is  five  minutes,  the 


J.    C.    SAI.A,    SAN    FRANCISCO 


meridian  must  be  changed  five  minutes  from  the  true  meridian  at  each 
point  where  side  shots  are  taken.  The  bearings  of  the  sights  may  be 
read  off  as  set  down,  but  in  plotting,  the  meridian  must  be  varied. 

The  angle  found,  the  lines  as  plotted  may  be  traced  on  a  piece  of 
tracing  paper  and  fitted  on  the  triangulation  points.  Each  station  is 
pricked  through,  and  through  each  station  must  be  drawn  two  lines  at 
right  angles,  one  due  north  and  south,  and  the  other  due  east  and  west. 
On  these  lines  fit  the  protractor. 

A  large  paper  protractor  is  used  for  plotting  side  sights.  The 
center  is  cut  out  close  to  the  graduations  which  are  numbered  from 
0°  to  3()0°.  Place  it  on  the  lines  drawn  at  right  angles  through  the 
stations  so  that  the  lines  pass  through  0°,  90°,  180°,  270°,  and  360°. 

Take  a  triangular  scale  and  paste  on  it  at  the  point  where  meas- 
urements commence,  a  piece  of  paper  about  a  quarter  of  an  inch  square 
or  smaller.  It  should  be  a  tough  paper.  Directly  opposite  the  zero 
mark  put  a  fine  needle  through  this  paper  and  through  the  station  on 
the  map.  The  scale  may  then  be  swung  around  in  a  circle. 

The  angle  is  first  read  and  the  scale  points  to  it.  The  distance 
is  then  read  off  on  the  scale  and  set  on  the  map.  It  may  be  seen  that 
the  process  is  a  duplicate  of  that  by  which  the  sights  were  taken.  The 
instrument  station  is  the  center  of  the  protractor,  and  the  angles  are 
read  off  the  same  as  on  the  instrument.  The  true  distance  is  read  on 
the  scale  and  plotted  on  the  map.  The  elevation  is  marked  on  it,  and 
when  ready  for  contour  work,  the  man  who  did  the  field  work  can 
draw  in  the  contours.  Any  draughtsman  may  plot  the  notes,  but  only 
the  original  surveyor  can  correctly  put  in  the  contours.  The  draughts- 
man may  make  contours  if  he  likes  from  the  original  notes  as  plotted, 
but  the  contours  should  not  be  inked  in  until  the  field  man  has  had  an 
opportunity  to  verify  them. 

Accuracy    of    Stadia    Work. 

Instances  are  on  record  of  stadia  lines  closing  with  an  error  of 
less  than  one  in  five  thousand,  which  is  a  better  result  than  can  be 
obtained  by  other  methods  of  topographical  surveying  and  certainly  is 
closer  than  many  farm  surveys.  Such  close  results  are  however, 


I38  ILLUSTRATED   CATALOGUE   OF 


exceptional,  and  there  must  have  been  present  conditions  which  cannot 
always  be  expected. 

For  careful  work,  the  error  may  be  from  one  in  seven  hundred  to 
one  in  fifteen  hundred.  It  may  be  made  very  much  less  as  experience 
with  the  work  increases.  It  is  closer  than  can  be  scaled  on  a  map  of 
the  scale  to  which  topographical  maps  are  usually  made,  so  it  is  as 

accurate  as  is  necessary. 

, 

In  plane  table  work  the  plotting  is  accurate  only  for  the  scale  to 
which  the  first  map  is  made  or  for  a  smaller  map  reproduced  from  the 
original.  Every  enlargement  increases  the  amount  of  error  if  any 
error  is  in  the  work.  With  stadia  surveying  it  is  not  so.  The  work 
may  be  plotted  to  any  scale  and  the  error  is  of  equal  amount  in  each 
plat.  If  the  reading  was  one  foot  wrong  it  is  only  one  foot  wrong 
whether  the  scale  is  one  thousand  feet  to  an  inch  or  fifty  feet. 

Uses    of    the    Map. 

A  survey  of  a  piece  of  country  thirty  miles  long  was  made  by  the 
stadia  method  with  running  triangulation,  and  topography  taken  with 
stadia  rod  for  a  distance  of  a  quarter  of  a  mile  on  either  side  of  the 
line.  The  line  was  run  approximately  on  the  grade  of  the  proposed 
canal.  The  work  was  plotted  and  contours  with  one  toot  intervals 
drawn.  Upon  this  was  located  the  canal  line  and  when  staked  in  the 
field  the  agreement  was  remarkable.  The  complete  notes  were  made 
in  the  office  from  the  map  and  very  little  change  was  necessary. 

A  canyon  in  the  interior  of  this  State  was  surveyed  for  a  short 
line  of  railroad  and  the  location  made  on  the  map.  This  location  was 
followed  on  construction  without  change. 

A  tract  of  land  was  surveyed  at  small  cost  and  on  the  map  was 
planned  the  subdivision.  All  the  roads  and  streets  were  laid  out,  a 
sewer  system  designed  and  grades  established.  A  few  monuments  were 
set  in  and  all  future  subdivision  of  that  piece  of  land  will  be  made  from 
the  map  which  was  filed,  and  the  measurements  will  be  taken  from  the 
monuments  as  starting  points.  Parks  and  cemeteries  were  also  laid  out 
on  this  map. 

It  is  possible  to  make  surveys  from  which  to  calculate  quantities 
for  grading.  Many  such  surveys  have  been  made  and  the  results  are 


J.    C.    SALA,    SAN    FRANCISCO 


139 


as  good  as  when  the  land  is  staked  out  in  small  squares.  The  work 
can  of  course  be  made  as  close  as  desired,  depending  entirely  upon  the 
care  taken. 

A  survey  has  recently  been  made  in  a  town  where  the  original 
field  notes  had  entirely  disappeared.  The  roads  were  all  winding,  and 
in  many  places  the  owners  of  property  had  encroached  on  the  street. 
A  careful  tape  survey  was  made  to  connect  monuments  which  were  set 
in,  and  the  fences  and  buildings  were  located  with  stadia  rods  from  each 
station.  The  work  was  plotted  on  a  large  scale  (forty  feet  to  an  inch). 
The  taped  lines  were  plotted  by  latitude  and  departures  and  the  side 
sights  plotted  in  as  described  before.  All  original  maps,  etc.,  were 
plotted  on,  and  the  original  lines  recovered  as  well  as  possible.  Then 
a  set  of  field  notes  were  made  from  the  map  and  run  in  on  the  ground. 

In  making  a  set  of  notes  from  the  map,  it  is  necessary  to  rule  it 
off  into  latitude  and  departure  squares  as  accurately  as  they  can  be 
plotted,  and  when  all  the  points  have  been  set  on  the  map,  their  posi- 
tion may  be  scaled  and  the  latitude  and  departure  of  each  point  set 
down.  The  bearing  and  distance  between  two  points  can  then  be 
calculated. 


140 


ILLUSTRATED   CATALOGUE   OF 


GRADIENTER    SCREW    TABLE. 

(COPYRIGHTED) 


This  Table  has  been  computed  by 

A.  BARION,  C.  E. 
Expressly  for  this  Catalogue. 


Multiples,  for  the  space  on  the  leveling  rod,  expressed  in  feet  and  decimals, 
obtained  by  two  revolutions  of  the  gradienter  screw. 


Angles  of 
Elevation. 

Multiples  for 
Direct 
Distance. 

Multiples  for 
Horizontal 
Distance. 

Angles  of 
Elevation. 

Multiples  for 
Direct 
Distance. 

Multiples  for 
Horizontal 
Distance. 

6         / 

0        / 

o. 

100.000 

100.000 

8.00 

98.888 

97.926 

0.15 

99-995 

99-993 

8.15 

.822 

-•799 

0.30 

.987 

.984 

8.30 

•754 

.669 

0.45 

•979 

•97° 

8-45 

.684 

•536 

1.00 

.967 

•954 

9.00 

•613 

•399 

I.I5 

•954 

•930 

9-15 

•539 

•257 

1.30 

•939 

.906 

9-30 

-465 

.113 

•923 

.877' 

9-45 

-387 

96.966 

2.00 

•905 

•843 

10.00 

•307 

.814 

2.15 

.884 

.807 

10.15 

.227 

-659 

2.30 

.862 

.768 

10.30 

•143 

.500 

2.45 

-837 

.722 

10.45 

•059 

•338 

3.00 

.811 

.674 

11.00 

97.972 

.172 

3-15 

-785 

•623 

11.15 

.883 

•  003 

3-30 

•753 

.566 

11.30 

•794 

95-830 

3-45 

.721 

.506 

n-45 

.701 

•654 

4.00 

.687 

•444 

12.00 

.607 

•474 

4-15 

.651 

•377 

12.15 

.511 

.291 

4-30 

.614 

.306 

12.30 

.414 

.104 

4-45 

-575 

.231 

12.45 

.313 

94.915 

5.00 

-534 

•154 

13.00 

.212 

.722 

5-15 

.492 

.070 

I3-I5 

.109 

.524 

5-30 

•444 

98.986 

I3-30 

.004 

-323 

5-45 

•397 

.897 

13-45 

96.896 

.121 

6.00 

•348 

.803 

14.00 

.788 

93-9I3 

6.15 

•297 

•707 

14.15 

.677 

.703 

6.30 

.246 

.606 

14.30 

•565 

.489 

6-45 

.188 

•503 

14-45 

•450 

.272 

7.00 

•133 

•395 

15.00 

•334 

.052 

7-15 

•075 

.285 

I5-I5 

.216 

92.829 

7-30 

.015 

.167 

I5-30 

.096 

.6OI 

7-45 

98.952 

.049 

15-45 

95-975 

•369 

J.    C.    SAI,A,    SAN   FRANCISCO 


GRADIENTER    SCREW    TABLE. 

(CONTINUED) 


Angles  of 
Elevation. 

Multiples  folpJuldpTelfcT 
Direct           Horizontal 
Distance.          Distance. 

=~=~=== 
Angles  of 
Elevation. 

—  - 
Multiples  foi 
Direct 
Distance. 

r  Multiples  for 
Horizontal 

16.00 

16.15 
16.30 
16.45 
17.00 

95.850 
.725 
.598 
.469 

-338 

92.137 
91.902 
.662 
.421 

0       / 

23.00 

23.15 
23-30 
23.45 
24.00 

91.660 
.484 

.307 
.128 
90.948 

84.374 
•056 

83.735 
.411 
.086 

17.30 

17-45 
18.00 
18.15 
18.30 
18.45 
19.00 

-205 
.071 
94.935 
-797 
•657 
•515 
•372 
.227 

90.923 
.671 
.417 

-158 
89.896 
.632 
•364 
.093 

24-15 
24.30 

24-45 
25.00 

25.15 
25.30 
25-45 
26.00 

.766 
•583 
.396 
.208 
.019 
89.829 
•636 
.441 

82.757 
.427 
.092 
81.757 
.419 
.078 

80-735 

I9-I5 

.080 

88.819 

26.15 

.246 

.042 

19.30 

J9-45 
20.00 

93-930 
.780 
.627 

•543 
.264 
87.980 

26.30 
26.45 
27.00 

•047 
88.848 
.646 

79.692 
•340 
78.086 

20.15 

•473 

.696 

27.15               .444                .620 

20.30 

•3i7 

.409 

27.30 

.242 

.270 

20.45 

.160 

•1*7 

27.45 

.035 

77.909 

21.00 

.000 

86.823 

28.00 

87.826 

s 
.546 

21.15 

92.839 

.527 

28.15 

.616 

.180 

21.30 

.676 

.228 

28.30 

•405 

76  .813 

21-45 

•511 

85.926 

28.45 

.192 

•  444 

22.00 

•343 

.621 

29.00 

86.977                 .073 

22.15 

•175 

•3*3 

29.15 

.761 

75.700 

22.30 

.005 

.002 

29.30 

•544 

•324 

22.45 

91.833 

84.690 

29.54 

•324 

•947 

' 

30.00 

.IO2 

.568 

SCIENTIFIC     BOOKS. 


At  dealers'  catalogue  prices  I  can  furnish  to  my  customers  all 
books — theoretical,  practical  or  for  reference  on  mathematics,  mechan- 
ics, hydrostatics,  hydraulics,  nautics,  civil,  mining,  mechanical  and 
electrical  engineering,  materials  of  construction  and  treatises  on  draw- 
ing maps  and  draughtsmanship  in  general. 


142 


ILLUSTRATED    CATALOGUE   OF 


INSTRUCTIONS. 
TO  DETERMINE  THE  TKUE  MERIDIAN  BY  TWO  EQUAL  ALTITUDES  OF  THE 

SUN. 


Set  up  the  transit  instrument  at  the  place  of  observation,  P  ;  see  that  there  is  no 
dead  motion  in  the  tangent-screws  and  tripod-legs  ;  slide  the  Solar  Keflector  into  the 
eye-piece  cap  ;  put  the  cover  with  the  small  hole  over  the  object-glass  ;  clamp  the 
vernier  of  the  horizontal  plate  to  zero ;  then  level  up  the  instrument,  turn  it  on  the 
lower  plate  center  toward  the  sun,  and  raise  the  telescope  till  the  sun's  image  appears 
)  on  the  reflc-ctor.   Clamp  the  telescope  axis  and  the  lower  plate  center,  and  bring  with 
)  the  vertical  axis  tangent  screw  and  with  the  lower  plate  tangent  screw  the  image  of 
(  the  sun  exactly  within  the  graduated  lines  of  the  reflector.  Note  the  time,  and  make 
it  so  that  the  forenoon  observation  will  correspond  nearly  in  time  with  one  of  the  col- 
umns of  the  correction  table.    Be  careful  that  the  position  of  the  instrument  is  not 
disturbed,  and  that  the  vernier  of  the  horizontal  plate  remains  at  zero ;  because   zero  ( 
isthe  starting-point  for  the  afternoon  observation.  ^ 

The  afternoon  observation  will  be  sooner  or  later,  as  the  case  may  be,  on  account 
of  the  declination  of  the  sun  ;  and  it  is  important  that  the  observer  should  beaware  of 
this,  so  that  he  may  not  put  any  reliance  on  exact  corresponding  meridian  distance  as 
to  time  for  the  afternoon  observation,  The  second  observation,  or  the  double-equal 
altitude  of  the  sun,  is  fast  or  slow :  but  the  observer  mu*t  not  lose  confidence  in  the 
accuracy  of  his  established  true  meridian  line  on  account  of  this  irregularity,  as  the 
table  will  afterwards  make  the  necessary  correction.  Taking  it  for  granted  that  the 
instrument  has  remained  undisturbed  in  the  same  position  during  the  time  since  the 
forenoon  observation  was  taken,  and  as  the  time  for  the  afternoon  equal  altitude  of  t  lie 
sun  is  approaching,  the  observer  has  to  loosen  carefully  the  horizontal  vernier  ( 
clamp,  and  slowly  turn  the  instrument  on  the  horizontal  circle  in  the  direction  the 
sun  has  moved.  As  soon  as  the  sun'a  image  begins  to  appear  on  the  reflector,  the 
observer  has  to  fasten  the  clamp  of  the  horizontal  vernier,  and  make  the  final  motion 
with  the  Horizontal  vernier  tangent  screw  alone.  The  utmost  precaution  has  to  be 
taken  not  to  move  the  lower  clamp  and  tangent-screw,  or  the  telescope  axis  tangent 
screw,  as  any  motion  on  either  ot  those  parts  will  make  the  observation  worthless. 

The  sun  is  moving  very  fast ;  two  seconds  of  time  can  be  distinctly  seen  on  the 
reflector'  the  observer  musi therefore  be  very  attentive  and  quick  :  he  must  follow 
with  the  horizontal  vernier  tangent  screw  the  oblique  course  of  the  sun  on  the  re- 
flector till  the  image  is  precisely  in  the  same  place  between  the  graduated  lines  as  by 
the  former  observation.  When  this  is  satisfactorily  done,  then  the  observer  has  to  find 
correctly  the  horizontal  angle,  and  make  the  necessary  corrections  for  the  true  me- 
ridian line,  as  shown  hereafter. 


J.    C.    SAI,A,    SAN   FRANCISCO 


DIRECTIONS 

FOR   THE   USE   OF  THE   TABLE   OF   CORRECTIONS. 

Find  in  the  ephemeris  of  the  sun  the  hourly  difference  of  the  sun's  declination  In  ' 
seconds,  for  the  date  of  observation;  and  find  in  the  correction  table  the  number 
which  corresponds  to  the  latitude  of  the  place  and  to  the  time  of  morning  observa- 
tion ,  multiply  the  number  in  the  correction-table  with  the  hourly  difference  of  the 
sun's  declination,  and  the  product  will  be  the  correction  in  minutes  of  arc. 

The  actual  or  abstract  multiplier  to  give  the  result  in  seconds  of  arc  is  sixty  times 
the  number  given  in  the  table  below  ;  but  we  have  divided  by  sixty,  so  as  to  give 
minutes  of  arc  at  once,  as  not  less  than  a  minute  of  arc  can  be  read  on  the  division  of 
a  transit  instrument. 

Between  Dec.  22d  and  June  22d  the  sun  is  moving  North,  or  the  north  polar  dis- 
tance is  decreasing,  and  the  correction  found  by  the  multiplier  must  be  SUBTRACTED 
from  the  angle  as  found  on  the  horizontal  plate  .between  the  fore  and  afternoon  ob- 
servations, and  the  line  bisecting  the  remaining  angle  will  be  the  true  meridian.  But 
between  June  22d  and  Dec  .22d,  when  the  sun  is  moving  South  or  the  north  polar  dis- 
tance is  increasing,  AI>D  the  correction  to  the  horizontal  angle,  as  found  in  the  read- 
ing of  the  instrument,  and  the  line  bisecting  the  sum  of  these  two  angles  will  be  the 
true  meridian. 

TABLE  OF  CORRECTIONS. 


I.ut, 


8 


32°|  0.18 
0.18 
0.19 


M° 
86° 
86° 

:<7" 

tap 

ayo 
400 
41o 

42° 
430 
44 

451 

4<;  > 

47" 
480 
4'J  ' 


0.19 

0.19 
0-19 
0.20 
0.20 
0.20 
0.20 
0.21 
0.21 
0.21 
0.22 
0.22 
0.23 
0.23 
0.23 


8t      9 


0.17  I    0.17 
0.18      0.17 

0.18       0.17 


0.18 
018 
0.18 
0.19 
0.19 
0.19 
0.19 
0.20 
0.20 
0.20 
0.21 
0.21 
0.22 
0.22 
0.22 


0.17 
0.17 
0.18 
0.18 
0.18 
0.18 
0.19 
0.19 
0.19 
0.20 
0.20 
0.20 
0.21 
0.21 
0.22 


9i 


0.16 
0.16 
0-17 
0.17 
0.17 
0.17 
0.17 
0.18 
0.18 
0.18 
0.18 
0.19 
0.19 
0.19 
0.20 
0.20 
0.20 
0.21 


10 


0.16 
0.16 
0.16 
0.16 
0.16 
0.17 
0.17 
0.17 
0.17 
0.18 
0.18 
0.18 
0.19 
0.19 


0.20 
0.20 


lOi 


0.15 
0.16 
0.16 
0.16 
0.16 
0.16 
0.17 
0.17 
0.17 
0.17 
0.18 
0.18 
0.18 
0.18 
0.19 
0.19 
0.20 
0.20 


11 


0.15 
0.15 
0.16 
0.16 
0.16 
0.16 
0.16 
0.17 
0-17 
0.17 
0-17 
0.18 
0.18 
0.18 
0.19 
0.19 
0.19 
0.20 


lit 


0.14 
0.15 
0.15 
0.15 
0.15 
0.16 
0.16 
0.16 
0.16 
0.17 
0.17 
0.17 
0.18 
0.18 
0.18 
0.19 
0.19 
0.19 


jgPSuostract 
the  product 

of  the 
multiplication 

between 
December  22d  J 
and  June  22d.  £ 


|^- Add  the 
product  of  the 
multiplication 

between 

June  22d  and 

Dec.  22d. 


EXAMPLE  I.  May  24th,  1881,  8:30  A.M.,  at  San  Francisco,  in  Jat.  37  deg.48min. 
north,  I  took  the  altitude  of  the  sun's  image;  and  seven  hours  afterwards,  at  3:30  P.M. 
I  had  the  same  altitude.  The  horizontal  angle  between  the  two  observations  mea- 
sured 168 deg.  33  min.,  and  the  hourly  differences  In  the  sun's  declination  in  the  ephem- 
eris was  27-46  seconds.  The  tabular  number  for  lat.  38deg.  and  8:30  A.M.  is 0.19  ; 
hence  correction  is :  27.46  x  0.19  gives  5  minutes  ;  horizontal  angle  is  168  deg.  33  min., 
from  which  deduct  5  min.,  leaving  168  deg.  28  min.,  which  divided  by  two  gives 
84  deg.  14  min.  for  the  true  meridian. 

EXAMPLE  II.  Sept.  10th,  1881,  at  11  o'clock  A.M.,  at  the  same  place  of  observa- 
tion, the  horizontal  angle  measured  at  1  P.M.  52  deg  41  min.;  the  hourly  difference  in 
the  sun's  declination  was  56.98  seconds.  The  tabular  number  for  38  deg.  and  11  A.M.is 
0.16;  hence  correction  is:  56.98  x  0.16  gives  9  minutes;  horizontal  angle  is  52  deg 
41  min.,  to  wtuch  add  9  min.,  making  52  deg.  50  min.,  which  divided  by  two  gives 
26  deg.  25  min.  for  the  Jrue  meridian. 

After  establishing  the  line  on  the  ground,  the  whole  manipulation  is  finished. 


144 


ILLUSTRATED   CATALOGUE   OF 


TABLE 

Of  Refractions  la  Declination  for  Solar-Compasses  and  Solar-Transits. 


Plus: 

By  SUN'S  DECLINATIONS  NOKTH, 

From   March   22d  to  Sept.  22d,  add;       t 

April.            \ 

For 

Hours 

Sun's  Declinations  in  Nautical  Aim.    *> 

V 

from 

I 

\ 

Lati. 

Me:id. 

.+  20° 

+  15°  ,  +  10° 

+  5°   < 

May.                     \ 

30° 

1. 

10 

15 

21 

27    ( 

\ 

n 

a- 

14 

19 

25 

31    ( 

_                  \ 

" 

3. 

20 

26 

32 

39    ( 

\ 

\ 

•' 

4. 

32 

39 

46 

52 

June. 

35° 

L 

2. 

15 
20 

21 
25 

27 
32 

33 
38 

*' 

3. 

26 

33 

39 

47 

— 

** 

4. 

39 

47 

56 

1  06 

400 

1. 

21 

27 

33 

40 

July 

r. 

2. 
3. 

25 
33 

32 
40 

39 
48 

46 

57 

/. 

** 

4. 

47 

55 

1  05 

1  18    ) 

45° 

1. 

27 

33 

40 

48    / 

" 

2. 

32 

39 

46 

52    / 

M 

3. 
4. 

40 
54 

47 
1  02 

56 
1  14 

1  06    ) 
1  32    ,v 

500 

1. 

33 

40 

48 

57 

2 

38 

46 

55 

1  06    / 

" 

3.' 
4. 

47 
1  00 

56 
1  45 

1  06 
2  00 

1  20    ) 
3  00    ( 

-22d-    ' 

••/  Minus: 

/  .  1  Oct 

BY  SUN'S  DECLINATIONS  SOUTH, 
From  Sept.  22d  to  March  22d,  substracl  :     ( 

For 

Hours 

Sun's  Declinations  in  Nautical  Aim.    , 

/         ^~ 

Lati. 

from 
Me  rid. 

-  50 

-  100 

-  150 

-  200  £ 

/           !  Nov. 

/   // 

/  // 

/   // 

/  //    ( 

/ 

30° 

1. 

40 

48 

56 

1  00     > 

/ 

2. 

46 

54 

1  10 

1  18     V 

/ 

u 

3. 

55 

1  06 

1  18 

1  36    C 

1  Dec. 

" 

4. 

1  19 

1  35 

1  57 

229    C 

35° 

1. 

,     48 

57 

1  06 

1  20    \ 

M 

2. 

;  55  1   i  04 

1  18 

1  34    <• 

" 

3. 

06          1  20 

1  40 

2  00     \ 

** 

4. 

40 

2  00 

2  30 

3  30    < 

Jan. 

400 

1. 

00 

1  08 

1  30 

1  40    ( 

• 

2. 

08 

1  20 

1  36 

2  00     f 

\                   — 

" 

3. 

20 

1  40 

2  00 

2  40     ' 

\ 

•* 

4- 

2  00 

2  30 

3  20 

5  00     ( 

\               Feb. 

450  . 

1. 

1  08 

1  30 

1  40 

2  00    ( 

\ 

2. 

1  20 

1  40 

2  00 

2  30    < 

\          i:- 

•• 

3. 

1  40 

2  00 

2  36 

3  30    <• 

\ 

" 

4. 

2  20 

3  00 

4  40 

8  00    ( 

\         March. 

500 

I. 

1  30 

1  40 

2  00 

2  40 

\ 

" 

2. 

1  36 

2  00 

2  30 

3  15 

X  i  -22d- 

I! 

3. 
4. 

2  30 
3  00 

2  45 
4  30 

3  30 

7  00 

5  00 
15  00 

J.    C.    SALA,    SAN   FRANCISCO 


145 


TABLE. 

Of  the  increase  or  decrease  of  the  Sun's  Declination  for  hourly  Differences 
from  5  seconds  to  60  seconds,  and  from  three  to  twelve  hours  of  time. 


45 


515 


57 


3  1 . 


1     45 


4  K 

5  !. 

6  h. 

7  h. 

8h. 

9  h. 

10  h. 

11  h. 

12  h. 

20 

25 

30 

35 

40 

45 

50 

55 

1  0( 

24 

30 

36 

42 

48 

54 

1  00 

1  06 

1  li 

28 

35 

42 

49 

56 

1  03 

1  10 

1  17 

1  2' 

32 

40 

48 

56 

1  04 

1  12 

1  20 

1  28 

1  3( 

3G 

45 

54 

1  03 

1  12 

1  21 

1  30 

1  39 

1  4 

40 

50 

1  00 

1  10 

1  20 

1  30 

1  40 

1  50 

2  0 

44 

55 

1  00 

1  17 

1  28 

1  39 

1  50 

2  01 

2  1 

48 

1  00 

12 

1  24 

1  3C 

1  48 

2  00 

2  12 

2  2 

52 

1  05 

18 

1  31 

1  44 

1  57 

2  10 

2  23 

2  3 

56 

10 

24 

1  38 

1  52 

2  06 

2  20 

2  34 

2  4 

1  00 

15 

30 

1  45 

2  00 

2  15 

2  30 

2  45 

3  0 

1  04 

20 

36 

1  52 

2  08 

2  24 

2  40 

2  56 

3  1 

I  08 

25 

42 

1  59 

2  16 

2  33 

2  50 

3  07 

3  2 

1  12 

30 

48 

2  06 

2  24 

2  42 

3  00 

3  18 

3  3 

1  16 

35 

54 

2  13 

2  32 

2  51 

3  10 

3  29 

3  4 

1  20 

40 

2  00 

2  20 

2  40 

3  00 

3  20 

3  40 

4  0 

1  24 

1  45 

2  06 

2  27 

2  48 

3  09 

3  30 

3  51 

4  1 

1  28 

1  50 

2  12 

2  34 

2  56 

3  18 

3  40 

02 

4  2 

1  32 

1  55 

2  18 

2  41 

3  04 

3  27 

3  50 

13 

4  3 

1  36 

2  00 

2  24 

2  48 

3  12 

3  36 

4  00 

24 

4  4 

1  40 

2  05 

2  30 

2  55 

3  20 

3  45 

4  10 

35 

5  0 

1  44 

2  10 

2  36 

3  02 

3  28 

3  54 

4  20 

46 

5  1 

1  48 

2  15 

2  42 

3  09 

3  36 

03 

4  30 

57 

5  2 

1  52 

2  20 

2  48 

3  16 

3  44 

12 

4  40 

5  08 

5  3 

1  56 

2  25 

2  54 

3  23 

3  52 

21 

4  50 

5  19 

5  4 

2  00 

2  30 

3  00 

3  30 

4  00 

30 

5  00 

5  30 

6  0 

2  04 

2  35 

3  06 

3  37 

4  08 

39 

5  10 

5  41 

6  1 

2  08 

2  40 

3  12 

3  44 

4  16 

48 

5  20 

5  52 

6  2 

2  12 

2  45 

3  18 

3  51 

4  24 

57 

5  30 

6  03 

6  3 

2  16 

2  50 

3  24 

3  58 

4  32 

5  06 

5  40 

6  14 

6  4 

2  20 

2  55 

3  30 

05 

4  40 

5  15 

5  50 

6  25 

7  0 

2  24 

3  00 

3  36 

12 

4  48 

5  24 

6  00 

6  36 

7  1 

2  28 

3  05 

3  42 

19 

4  56 

5  33 

6  10 

6  47 

7  2 

2  32 

3  10 

3  48 

26 

5  04 

5  42 

6  20 

6  58 

7  3 

2  36 

3  15 

3  54 

33 

5  12 

5  51 

6  30 

7  09 

7  4 

2  40 

3  20 

4  00 

40 

5  20 

6  00 

6  40 

7  20 

8  0 

2  44 

2  48 
2  52 

3  25 
3  30 
3  35 

06 
12 
18 

4  47 
4  54 
5  01 

5  28 
5  36 
5  44 

6  09 
6  18 
6  27 

6  50 
7  00 
7  10 

7  31 
7  42 
7  53 

8  1 

8  2 
8  3 

2  56 
3  00 
3  04 
3  08 

3  40 
3  45 
3  50 
3  55 

24 
30 
36 
42 

5  08 
5  15 
5  22 
5  29 

5  52 
6  00 
6  08 
6  16 

6  36 
6  45 
6  54 
7  03 

7  20 
7  30 
7  40 

7  50 

8  04 
8  15 
8  26 
8  37 

8  4 
9  0 
9  1 
9  2 

3  12 
3  16 
3  20 

4  00 
4  05 
4  10 

48 
54 
5  00 

5  36 
5  43 
5  50 

6  24 
6  32 
6  40 

7  12 
7  21 
7  30 

8  00 
8  10 
8  20 

8  48 
8  59 
9  10 

9  3 
9  4 
10  0 

3  24 
3  28 
3  32 
3  36 
3  40 
3  44 
3  48 
3  52 
3  56 
4  00 

4  15 
4  20 
4  25 
4  30 
4  35 
4  40 
4  45 
4  50 
4  55 
5  00 

5  06 
5  12 
5  18 
5  24 
5  30 
5  36 
5  42 
5  48 
5  54 
6  00 

5  57 
6  04 
6  11 
6  18 
6  25 
6  32 
6  39 
6  46 
6  53 
7  00 

6  48 
6  56 
7  04 
7  12 
7  20 
7  28 
7  36 
7  44 
7  52 
8  00 

7  39 
7  48 
7  57 
8  06 
8  15 
8  24 
8  33 
8  42 
8  51 
9  00 

8  30 
8  40 
8  50 
9  00 
9  10 
9  20 
9  30 
9  40 
9  50 
10  00 

9  21 
9  32 
9  43 
9  54 
10  05 
10  16 
10  27 
10  38 
10  49 
11  00 

jrv^-^^. 

10  1 
10  2 
10  3 
10  4 
11  0 
11  1 
11  2 
11  3 
11  4 
12  0 
s-^~*~ 

3(5 


146 


ILLUSTRATED   CATALOGUE  OF 


TABLE. 


AZIMUTHS   OF   POLARIS, 

At  the  time  of  greatest  elongation,  from  the  year  1881  to  1900, 
and  from  latitude  30deg.  to  49deg.  north. 

COMPUTED  BY  W.  J.  LEWIS,  C.  E. 


year.  L.  30°  L.  31°  L.  32°  L.  33° iL.  34°  L.  35°  L.  36°  L.  37°  L.  38°  L.  39°  year. 


J.    C.    SALA,    SAN    FRANCISCO 


I47 


TABLES. 


IIOWIIIK  lauies  give  me  greaiebi  eastern  ana  western  Elongation  of  the  North 
)       Star  (  Polaris),  in  common  clock  time,  for  every  third  day  in  the  year  when  the  star 

L        is  visible. 

EASTERN  ELONGATION. 

|                                                                                                                                                                                                                                              f 

Day 

) 

of 
Month 

April. 

May. 

June. 

July.          August. 

September.^ 

h  .  m  in 

h    min 

.  min. 

h,  min.          h    min 

h    min 

1 

6  39  A.M 

4  41  A.M 

2  39  A.M 

0  41  A.M    10  35  P.M 

8  32  P.M 

4 

6  27   " 

4  29    " 

2  28    " 

0  30   "        10  23    " 

8  20  " 

7 

6  15  " 

4  17    " 

2  16    " 

0  18  «        10  12  " 

8  08  " 

10 

6  03   " 

4  05    " 

2  04    " 

0  06 

10  00    " 

7  56  " 

13 

5  52   " 

3  53    " 

1  52    « 

11  49  1  M 

9  48   '« 

7  45  " 

16 

5  40     • 

3  41 

1  40    «• 

11  37 

9  36  " 

7  33  "    ( 

19 

5  28     • 

3  30 

1  28    •« 

11  25 

9  24   " 

7  21  " 

22 

5  16    ' 

3  18 

1  17    " 

11  14 

9  12   " 

7  09  " 

25 

5  04     • 

3  06 

1  05    " 

11  02 

9  01   " 

6  57  " 

28 

4  52    ' 

2  54 

0  53    " 

10  50 

8  49    " 

6  46  " 

31 



2  42 



10  38 

8  37  " 



WESTERN    ELONGATION. 

Day 

of 

October. 

November. 

December. 

January. 

February. 

March. 

Month 

h    min 

h.  min. 

h.  min. 

h.  min. 

h-  min. 

h.  min. 

1 

6  27  A".  M 

4  24  A.  M 

2  26  A.M 

0  27  A.M 

10  21  P.M 

8  31  P,M 

4 

6  15   " 

4  13 

2  14   " 

0  15   " 

10  09    " 

8  18   " 

7 

6  03   " 

4  01 

2  02   " 

12  00  P.M 

9  58    " 

8  06    " 

10 

5  51   " 

3  49 

1  51    " 

11  48   " 

9  46    " 

7  55    " 

13 

5  39   " 

3  37 

1  39   " 

11  36    " 

9  34    " 

7  44    " 

16 

5  27  " 

3  25 

1  27    " 

11  24   " 

9  22    " 

7  32    " 

19 

5  16   " 

3  13 

1  16   " 

11  12     • 

9  10    " 

7  20    "    ( 

22 

5  04   " 

3  02 

1  04   " 

11  01     ' 

8  59    " 

7  08    "    ( 

25 

4  52    " 

2  50 

0  52   " 

10  49     • 

8  47    " 

6  56    "    ( 

28 

4  40  " 

2  38 

0  41   " 

10  36     ' 

8  35   " 

644    "    ( 

31 

4  28  " 

0  30   " 

10  25     • 



6  33    "    } 

An  approximation  to  the  true  meridian  m  ght  be  ob-                  . 
tained  by  sighting  on  the  Pole  Star  at  the  instant  when               ,-W-.                             ^ 
it  is  on  the  same  vertical  plane  with  Alioth.    TheNorth               \       • 
Star  is  exactly  in  the  true  meridian  26  minutes  lp,Jtoe 
after  it  has  been  in  the  same  vertical  plane  with  Alioth,                                                  ( 
and  may  be  sighted  after  that  i  nterval  of  time  with  per-                                                  ) 

feet  accuracy.                                                                                                                    ) 

On  the  first  day  of  January,  1882,  the  right  ascen- 
sion of  Polaris  will  be:  In.  15m.  30sec.,  and  of  Alioth                                                  ) 
13  h   42m    t3sec.    When  therefore  Polaris  arrives  at 

the  meridian,  Alioth  will  be  27  m.  23  sec.  to  the  East.                                                    ( 

Hence  when  Alioth  is  directly  under  Polaris,  or  in                                                  ( 
the  same  vertical  plane,  the  pole  is  to  the  West  of  this                                                  ( 
plumb  line,  ranging  from  iOmin.  38  sec.  in  arc  in  lat. 
30deg.  north  to  14  min.  2sec.  in  lat.  49  deg.  north.                                                    * 

.  The  azimuth  for  every  second  degree  of  latitude  is                                         -JL      j 

shown  in  the  following  table:                                                                              /  -.      » 

Lat. 
28° 

10  27 

36°        11  23        44° 

III.     0.                                                                                                            /                           %t       I 

12  48                                   ,-'          >  '> 

10  38 

38°        11  41         46° 

13  15             -,.          ..,-"  *,      /       \ 

32° 

10  51 

40°        12  01         480 

13  46         -'      "'*"                '#          > 

340 

11  06 

42°        12  23        49° 

14  02        ^            ft 

148 


ILLUSTRATED   CATALOGUE   OF 


EXPLANATORY  NOTES. 


EXPLANATION  OF  THE  TABLES. 


chains. 
As  CO  min. :  26  min.  6  sec.  :  :  5517.205 


chains. 

24.00  the  distance  required. 


Tables  I  and  1 1. 

Table  I  gives  the  length  of  a  degree  of  latitude,  in  chains,  for  every  minute  of 
latitude  between  29  and  49  degrees,  calculated  by  the  Formula  Dm  —  5523.8724— 
27.7425  cos  2  I  +  .0592  cos  4  I,  in  which  Dm  represents  a  degree  of  the  meridian, 
and  I,  the  middle  latitude. 

Table  II  gives  the  length  c^a  degree  of  longitude,  in  chains,  for  every  minute  of 
latitude  between  29  and  49  degrees,  calculated  by  the  formula  Dp  =  5&S7.7439  cos  I 
-4.6337  cos  3  I  +  0058  cos  5  I,  in  which  Dp  represents  a  degree  of  the  parallel  and 
I,  the  latitude. 

These  tables  are  useful  for  converting  linear  into  angular,  and  angular  into  linear 
meusure,  as  well  as  for  determining  the  convergencies  and  divergencies  of  the 
nit  ridians,  on  the  spheroidal  surface  of  the  earth. 

PROBLEMS  AND  EXAMPLES. 

1.     Given  thf  latitudes  of  any  two  places  on  the  same  meridian,  to 
Jind  the  distance  between  them. 

RCLE.— Find,  from  Table  I,  the  length  of  a  degree  of  the  meridian  at  each 
latitude,  and  take  half  their  sum  for  the  mean  length  of  a  degree.  Then  say,  as  60 
minutes  is  to  the  difference  of  latitude,  so  is  the  mean  length  of  a  degree  to  the 
distance  required.  / 

The  latitude  of  the  Monte  Diablo  Base  Line,  is  37  deg.  52  min.  47  sec.,  and  that  ( 
of  the  1st,  Standard  North,  38  deg.  18  min,  53  sec. ;  what  is  the  meridional  distance  ( 
between  them?  ( 


2.  Given  the  distance  between  any  two  places  on  the  same  meridian , 
and  the  latitude  of  one  of  them  to  find  their  difference  of  latitude. 

RULE.— Find,  from  Table  I,  the  length  of  a  degree  of  the  meridian,  in  the 
given  latitude,  and  also  in  that  differing  from  it,  by  the  meridional  distance, 
converted  into  an  arc  at  the  rate  of  52  seconds  per  mile,  and  take  half  their  sum 
for  the  mean  length  of  a  degree.    Then  say,  as  the  mean  length  of  a  degree    J 
is  to  the  meridional  distance,  so  is  60  minutes  to  the  difference  of  latitude  re-   ( 
quired.  < 

The  latitude  of  the  Monte  Diablo  Base  Line,  is  37  deg.  52  min.  47  sec.;  what  is  < 

the  latitde  of  the  1st  Standard  North,  the  meridional  distance  being  30  miles  ?  < 

chains.       chains. 

As  5517.205    :    2400  :  :  60  min.  :  26  min.  6  sec,  the  difference  of  latitude  required.  ( 

3.  Given  the  longitudes  of  any  two  places,  on  the  same  parallel,  in  a   ( 

given  latitude,  to  find  the  distance  between  them. 

RULE.— Find,  from  Table  II,  the  length  of  a  degree  of  longitude  in  the  given 
latitude:  and  say,  as  60  minutes  is  to  the  difference  of  longitude,  so  is  the 
length  of  the  degree  of  longitude  to  the  distance  required. 

The  longitude  of  Monte  Diablo  Meridian  is  121  deg.  54  min.  49  sec.,  and  that  ( 
of  Range  1  East,  121  deg.  21  min.  53  sec. ;  what  is  the  distance  between  them,  on  ) 
t  lie  Base  Line,  in  latitude  37  deg.  52  miu.  47  sec.? 

chains       chains 
As  60  min. :  32  min.  56  sec.  : :  4372.51    :    2400,  the  distance  required.  ) 


J.    C.    SALA,    SAN    FRANCISCO 


149 


EXPLANATORY  NOTES. 


^  4.     (riven  the  distance  between  any  two  places  on 
in  a  given  latitude,  to  find  their  difference  o 
)       RULE.— Find  from  Table  II,  the  length  of  degree  of  longitude  in  the  given 
?    latitude  ;  and  say,  as  the  length  of  the  degree  of  longitude  is  to  the  given  distance, 
so  is  60  minutes  to  the  difference  of  longitude. 

The  longitude  of  the  Monte  Diablo  Meridian,  is  121  deg   54  min.  49  sec  :  what  is 
)   the  difference  of  longitude  to  Range  5  East,  the  distance'  on  the  Base 'Line,  in 
\    latitude  37  deg.  52  min .  47  sec.,  being  30  miles? 
)  chains,    chains. 

As  4373  51:  2400:      60  min.:  32  min.  56  sec,  the  difference  of  longitude  required. 

(  5.  (riven  the  distance  between  two  meridians,  on  any  parallel,  in  a 
given  latitude,  to  find  the  convergency  of  the  meridians  for  any 
distance  north  of  that  parallel. 

UULE.— Find  the  length  of  a  degree  of  longitude,  at  each  latitude,  by  the  fore- 
going rules;  and  say,  as  the  greater  of  the  two  lengths  is  to  their  difference,  so  is 
'    the  given  distance  to  the  convergency  required. 

'  The  distance  between  Ranges  1  and  2  on  the  1st  Standard  South,  is  6  miles, 

f  what  is  the  convergency  of  the  two  range  lines  at  the  2d  Standard  North,  the  me. 

^  riiiional  distance  being  30  miles? 

?  chains,    chains,  chains,  chains. 

.'  As  4346. 66  :  26.07  :   :  480  :    2.88,  the  convergency  required. 

;  i>.  (riven  the  distance  between  two  meridians,  on  any  parallel  in  a 
given  latitude,  to  find  the  divergency  of  the  meridians  for  any 
distance  south  of  that  parallel. 

RULE,— Find  the  length  of  a  degree  of  longitude,  at.  each  latitude,  by  the  tore- 
\  going  rules ;  and  say,  as  the  less  of  the  two  lengths  is  to  their  difference,  so  is 
)  the  given  distance  to  the  divergency  required. 

<"       The  distance  between  Ranges  1  and  2,  on  the  1st  Standard  South,  is  6  miles ; 
)    what  is   the  divergency  of  the  two  range  lines  at  the  2d  Standard  South,  the 
meridional  distance  being  24  miles? 

chains,     chains,    chains,    chains. 
As  4393.00  :  20.34  :  :  480    :    2.22,  the  divergency  required. 

Table    III. 

This  table  gives  the  divergency  of  the  Parallel  of  Latitude  from  the  Prime 

Vertical,*  or  perpendicular  to  the  meridian,  on  the  spheroidal  surface  of  the  earth-  { 

at  every  second  degree  of  latitude,  from  23  to  43   degrees,  for   any   number  of  / 

miles  from  1  to  36;  and  is  useful  in  running  a  parallel  of  latitude  by  fore  and  V 

back  sighting.  ( 

•The  length  of  a  degree  of  the  Prime  Vertical  may  be  calculated  by  the  Formula  •, 

)    Dv=  5551  6748-18  6536  cos  2J  +.0940  cos  4  I ;  in  which  Dv  represents  a  degree  of  \ 

t    the  Prime  Vertical,  in  chains,  and  I  the  latitude.  C 

EXAMPLE. 

If  a  line  commenced  on  the  parallel  of  37  degrees  north  latitude,  be  ^tended 
east  or  west,  27*  miles,  by  fore  and  back  sighting,  what  distance  will  its  terminus 
be  south  of  that  parallel  ? 

chains. 
The  table  gives  for  27  miles  in  latitude  37  deg.  . .  5.52 


The  mean  o 


f  which  is  .....................  5.73  the  distance  required.  ; 


150 


ILLUSTRATED   CATALOGUE   OF 


T  A  B  L  E .  I  • 
Length  of  a  Degree  of  Latitude. 


/ 

290 

30° 

310 

320 

330 

340 

350 

360 

37° 

380 

/  ' 

chains. 

chains. 

chains. 

chains. 

chains. 

chains. 

chains. 

chains. 

chains. 

chains 

0 

509-15 

5509-97 

5510-82 

5511-67 

5512-55 

5513-44 

5514-34 

5515-25 

5516-lf 

5517-11 

0 

)  1 

09-16 

09-99 

10-83 

11-69 

12-56 

13-45 

14-35 

15-27 

16-19 

17-13 

1 

,'    2 

09-17 

10-00 

10-84 

11-70 

12-58 

13-47 

14-37 

15-28 

16-21 

17-14 

2 

3 

09-19 

10-01 

10-86 

11-72 

12-59 

13-48 

14-38 

15-30 

16-22 

17-M 

3? 

4 

09-20 

10-03 

10-87 

11-73 

12-61 

13-50 

14-40 

15-31 

16-24 

17-17 

*( 

5 

09-21 

10-04 

10-89 

11-75 

12-62 

13-51 

14-42 

15-33 

16-25 

17-19 

5? 

6 

09-23 

10-06 

10-90 

11-76 

12-64 

13-53 

14-43 

15-34 

16-27 

17-20 

6> 

7 

09-24 

10-07 

10-91 

11-78 

12-65 

13-54 

14-45 

15-36 

16-28 

17-22 

7) 

H 

09-25 

10-08 

10-93 

11-79 

12-67 

13-56 

14-46 

15-38 

16-30 

17-23 

8) 

g 

09-27 

10-10 

10-94 

11-81 

12-68 

13-57 

14-48 

15-39 

16-32 

17-25 

9 

10 

09-28 

10-11 

10-96 

11-82 

12-70 

13-59 

14-49 

15-41 

16-33 

17-27 

10 

11 

09-30 

10-13 

10-97 

11-83 

12-71 

13-60 

14-51 

15-42 

16-35 

17-28J11 

12 

09-31 

10-14 

10-99 

11-85 

12-73 

13-62 

14-52 

15-44 

16-36 

17-3012 

13 

09-32 

10-15 

11-00 

11-86 

12-74 

13-63 

14-54 

15-45 

16-38 

17-3113 

14 

09-34 

10-17 

11-01 

11-88 

12-76 

13-65 

14-55 

15-47 

16-39 

17-3314 

15 

09-35 

10-18 

11-03 

11-89 

12-77 

13-66 

14-57 

15-48 

16-41 

17-3415 

16 

09-36 

10-19 

11-04 

11-91 

12-79 

13-68 

14-58 

15-50 

16-42 

17-3616 

17 

09-38 

10-21 

11-06 

11-92 

12-80 

13-69 

14-60 

15-51 

16-44 

17-3817 

18 

09-39 

10-22 

11-07 

11-94 

12-81 

13-71 

14-61 

15-53 

16-46 

17-3918 

19 

09-41 

10-24 

11-09 

11-95 

12-83 

13-72 

14-63 

15-54 

16-47 

17-4119 

20 

09-42 

10-25 

11-10 

11-96 

12-84 

13-74 

14-64 

15-56 

16-49 

17-4220 

21 

09-43 

10-26 

11-11 

11-98 

12-86 

13-75 

14-66 

15-57 

16-50 

17-4421 

22 

09-45 

10-28 

11-13 

11-99 

12-87 

13-77 

14-67 

15-59 

16-52 

17-4522 

23 

09-46 

10-29 

11-14 

12-01 

12-89 

13-78 

14-69 

15-61 

16-53 

17-47 

23 

24 

09-47 

10-31 

n-ie 

12-02 

12-90 

13-80 

14-70 

15-62 

16-55 

17-49 

24 

25 

09-49 

10-32 

11-17 

12-04 

12-92 

13-81 

14-72 

15-64 

16-56 

17-50 

25 

26 

09-50 

10-33 

11-19 

12-05 

12-93 

13-83 

14-73 

15-65 

16-58 

17-52 

20 

27 

09-51 

10-35 

11-20 

12-07 

12-95 

13-84 

14-75 

15-67 

16-60 

17-53 

27 

28 

09-53 

10-36 

11-21 

12-08 

12-96 

13-86 

14-76 

15-68 

16-61 

17-55 

28 

29 

09-54 

10-38 

11-23 

12-10 

12-98 

13-87 

14-78 

15-70 

16-63 

17-56 

29 

30 

09-56 

10-39 

11-24 

12-11 

12-99 

13-89 

14-79 

15-71 

16-64 

17-58 

30 

31 

09-57 

10-41 

11-26 

12-12 

13-01 

13-90 

14-81 

15-73 

16-66 

17-60 

31 

32 

09-58 

10-42 

11-27 

12-14 

13-02 

13-92 

14-82 

15-74 

16-67 

17-61 

32 

33 

09-60 

10-44 

11-29 

12-15 

13-04 

13-93 

14-84 

15-76 

16-69 

17-63 

33 

34 

09-61 

10-45 

11-30 

12-17 

13-05 

13-95 

14-86 

15-77 

16-70 

17-64 

34 

35 

09-63 

10-46 

11-31 

12-18 

13-07 

13-96 

14-87 

15-79 

16-72 

17-66 

35 

3f 

09-64 

10-48 

11-33 

12-20 

13-08 

13-98 

14-89 

15-81 

16-74 

17-67 

36$ 

37 

09-65 

10-49 

11-34 

12-21 

13-10 

13-99 

14-90 

15-82 

16-75 

17-69 

•" 

38 

09-67 

10-50 

11-36 

12-22 

13-11 

14-01 

14-92 

15-84 

16-77 

17-71 

38  < 

39 

09-68 

10-52 

11-37 

12-24 

13-13 

14-02 

14-93 

15-85 

16-78 

17-7,2 

39  r 

40 

09-69 

10-53 

11-39 

12-26 

13-14 

14-04 

14-95 

15-87 

If/80 

17-74 

40 

41 

09-71 

10-55 

11-40 

12-27 

13-16 

14-05 

14-96 

15-88 

16-81 

17-75 

41? 

42 

09-72 

10-56 

11-42 

12-29 

13-17 

14-07 

14-98 

15-90 

16-83 

17-77 

42  (' 

43 

09-74 

10-57 

11-43 

12-30 

13-18 

14-08 

14-99 

15-91 

16-84 

17-78 

43) 

44 

09-75 

10-59 

11-44 

12-31 

13-20 

14-10 

15-01 

15-93 

16-86 

17-80 

44  ,> 

45 

09-76 

10-60 

11-46 

12-33 

13-21 

14-H 

15-02 

15-94 

16-88 

17-82 

45) 

4f 

09-78 

10-62 

11-47 

12-34 

13-23 

14-13 

15-04 

15-96 

16-89 

17-833 

4<;', 

47 

09-79 

10-63 

11-49 

12-36 

13-24 

14-14 

15-05 

15-98 

ic-yi 

17-85 

47  '• 

48 

09-80 

10-65 

11-50 

12-37 

13-26 

14-16 

15-07 

15-99 

16-92 

17-86 

48 

49 

09-82 

10-66 

11-52 

12-39 

13-27 

14-17 

15-08 

16-01 

16-94 

17-88 

49' 

50 

09-83 

10-67 

11-53 

12-40 

13-29 

14-19 

15-10 

16-02 

16-95 

17-89 

50 

51 

09-85 

10-69 

11-54 

12-42 

13-30 

14-20 

15-11 

16-04 

16-97 

17-91 

MS 

52 

09-86 

10-70 

11-56 

12-43 

13-32 

14-22 

15-13 

16-05 

16-98 

17-93 

V2 

53 

09-87 

10-72 

11-57 

12-45 

13-33 

14-23 

15-15 

16-07 

17-00 

17-94 

">3 

54 

09-89 

10-73 

11-59 

12-46 

13-35 

14-25 

15-16 

16-08 

17-02 

17-96 

54 

r>r 

09-90 

10-74 

11-60 

12-48 

13-36 

14-26 

15-18 

16-10 

17-03 

17-97 

r>r> 

56 

09-92 

10-76 

11-62 

12-49 

13-38 

14-28 

15-19 

16-11 

17-05 

17-.)'.) 

56 

57 

09-93 

10-77 

11-63 

12-51 

13-39 

14-29 

15-21 

16-13 

17-06 

18-00 

57 

58 

09-94 

10-79 

11-65 

12-52 

13-41 

14-31 

15-22 

16-15 

17-08 

18-02 

58 

59 

09-96 

10-80 

11-66 

12-53 

13-42 

14-32 

15-24 

16-16 

17-09 

18-04 

59 

6C 

09-97 

10-82 

11-67 

12-55 

13-44 

14-34 

15-25 

16-18 

17-H 

18-05 

to 

J.    C.    SAI<A,    SAN   FRANCISCO 


•   TABLE   i- 
Length  of  a  Degrte  of  Latitude, 


390 

40° 

410 

42° 

chains. 

chains. 

chains. 

chains. 

5518-05 

5519-00 

519-96 

520-92 

18-07 

19-02 

19-97 

20-93 

18-08 

19-03 

19-99 

20-95 

18-10 

19-05 

20-00 

20-96 

18-11 

19-06 

20-02 

20-98 

18-13 

19-08 

20-04 

21-00 

18-15 

19-10 

20-05 

21-01 

18-16 

19-11 

20-07 

21-03 

18-18 

19-13 

20-08 

21-04 

18-19 

19-14 

20-10 

21-06 

18-21 

19-16 

20-12 

21-08 

18-22 

19-18 

20-13 

21-09 

18-24 

19-19 

20-15 

21-11 

18-26 

19-21 

20-16 

21-12 

18-27 

19-22 

20-18 

21-14 

18-29 

19-24 

20-20 

21-16 

18-30 

19-25 

20-21 

21-17 

18-32 

19-27 

20-23 

21-19 

18-34 

19-29 

20-24 

21-20 

18-35 

19-  30 

20-26 

21-22 

18-37 

19-32 

20-28 

21-24 

18-C8 

19-33 

20-29 

21-25 

18-40 

19-3f 

20-31 

21-27 

18-41 

19-37 

20-32 

21-29 

18-43 

19-38 

20-34 

21-30 

>     18-45 

19-40 

20-30 

21-32 

,      18-4f. 

19-41 

20-37 

21-33 

18-48 

19-43 

20-39 

21-35 

^        IH'4'.I 

19-45 

20-40 

21-36 

»      18-51 

19-46 

20-42 

21-38 

)     18-53 

19-48 

20-44 

21-40 

L     18-54 

19-49 

20-45 

21-41 

I     18-5(1 

19-51 

20-47 

21-43 

J      18-57 

19-53 

20-48 

21-45 

I      18-5'J 

19-5 

20-50 

21-46 

'•>     18-00 

19-5 

20-52 

21-48 

')     18-62 

19-5 

20-53 

21-48 

1     18-64 

19-59 

20-55 

21-51 

3     18-65 

19-6 

20-56 

21-53 

3     18-67 

19-6 

20-58 

21-54 

3     18-68 

UN; 

20-60 

21-56 

1     18-70 

19-6 

20-6 

21  -51 

2     18-72 

19-6 

20-63 

21-M 

3     18-73 

19-6 

20-64 

21-61 

4     18-75 

19-7 

20-6 

21-65 

5     18-7f 

19-7 

20-6 

21-64 

6     18-78 

19-7 

20-69 

21  -6£ 

7     18-7r 

19-7 

20-7 

21  -6r 

8     18-81 

19-7 

20-7 

21-61 

9     18-8J 

19-7 

20-7 

21-7f 

0     18-84 

19-8 

20-7 

21-75 

1     18-8f 

19-8 

20-7 

21-74 

2     18-8r 

19-8 

20-7 

21-7? 

3     18-81 

19-8 

20-8 

21-7r 

4      18-9] 

19-8 

20-8 

21-7* 

5     18-95 

19-8 

20-84 

21-8( 

6     18-94 

19-8 

20-85 

21  -85 

7      18-9J 

19-9 

20-87 

21  -K 

8     18-9r 

19-9 

20-88 

21-8J 

9     18-9J 

19-9 

20-9C 

21-8C 

0     19-(X 

19-9 

20-95 

21-8J 

24-59  25-56  26'6_  _.  _ 

24-61  25-57  26-54  27-50  4S 

24-62  25-59  26-56  27-52  BC 

24-64  25-61  26-5 


152 


ILLUSTRATED    CATALOGUE   OP 


.  T  A  B  L  E.  II . 
Length  of  a  Degree  of  Longitude. 


>r 

•^X^N^- 

29° 

•^s^-s-<-s 

30° 

V^-N^^-'- 

31° 

i^-^~^r~ 

32° 

^S^S^s^. 

330 

^^^~S-^ 

340 

/~^^*^^ 

35° 

S^S^r* 

36° 

^•v_^v~/-v 

37° 

^**^-*~j-* 

38° 

**_/~ 
/ 

1 

chains. 

chains. 

chsiins. 

chains. 

chains 

chains. 

chains. 

chains. 

chains. 

chains. 

I  ° 

843-17 

795-82 

747-01 

4696-75  4645-06 

4591-96 

4537-45 

4481-56 

4424-29 

4365-68 

1) 

I  1 

42-40 

95-02 

46-19 

95-90 

44-19 

91-06 

36-53 

80-61 

23-33 

64-69 

1 

1 

41-62 

94-22 

45-36 

95-05 

43-32 

90-16 

35-61 

79-67 

22-36 

63-70 

2 

3 

40-84 

93-42 

44-53 

94-20 

42-44 

89-26 

34-69 

78-73 

21-40 

62'72 

3 

4 

40-06 

92-61 

43-71 

93-35 

41-57 

88-37 

33-77 

77-78 

20-43 

61-73 

4 

5 

39-28 

91-81 

42-88 

92-50 

40-69 

87-47 

32-84 

76-84 

19-46 

60-74 

5 

6 

38-50 

91-01 

42-05 

91-65 

39-82 

86-57 

31-92 

75-89 

18-49 

59-75 

6 

7 

37-72 

90*20 

41-22 

90-80 

38-94 

85-67 

31-00 

74-95 

17-53 

58-76 

7 

8 

36-94 

89-40 

40-39 

89-94 

38-06 

84-77 

30-08 

74-00 

16-56 

57-77 

8 

9 

36-16 

88-59 

39-56 

89-09 

37-19 

83-87 

29-15 

73-05 

15-59 

56-77 

g 

10 

35-38 

87-79 

38-73 

88-24 

36-31 

82-97 

28-23 

72-11 

14-62 

55-78 

10 

Ul 

34-60 

86-98 

37-90 

87-38 

35-43 

82-07 

27-30 

71-16 

13-65 

54-79 

11 

'12 

33-82 

86-18 

37-07 

86-53 

34-55 

81-17 

26-38 

70-21 

12-68 

53-80 

12 

i:( 

33-04 

85-37 

36-24 

85-67 

33-68 

80-26 

25-46 

69-26 

11-71 

52-81 

13 

14 

32-26 

84-56 

35-41 

84-82 

32-80 

79-36 

24-53 

68-32 

10-74 

51-81 

14 

15 

31-47 

83-76 

34-58 

83-96 

31-92 

78-46 

23-60 

67-37 

09-77 

50-82 

15 

H 

30-69 

82-95 

33-75 

83-11 

31-04 

77-56 

22-68 

66-42 

08-80 

49-83 

i<; 

17 

29'91 

82-14 

32-92 

82-25 

30'lfe 

76-65 

21-75 

65-47 

07-82 

48-83 

17 

18 

29-12 

81-33 

32-08 

81-40 

29-28 

75-75 

20-83 

64-52 

06-85 

47-84 

18 

1! 

28-34 

80-52 

31-25 

80-54 

28-40 

74-85 

19-90 

63-57 

05-88 

46-84 

19 

2! 

27-55 

79-71 

30-42 

79-68 

27-52 

73-94 

18-97 

62-62 

04-91 

45-85 

20 

\21 

26-77 

78-90 

29-58 

78-82 

26-64 

73-04 

18-04 

61-67 

03-93 

44-85 

21 

'22 

25-98 

78-09 

28-75 

77-97 

25-75 

72-13 

17-11 

60-72 

02-96 

43-85 

22 

23 

25-20 

77-28 

27-92 

77-11 

24-87 

71-23 

16-19 

59-77 

01-98 

42-86 

23 

24 

24-41 

76-47 

27-08 

76-25 

23-99 

70-32 

15-26 

58-81 

01-01 

41-86 

24 

26 

23-62 

75-66 

26-25 

75-39 

23-11 

69-41 

14-33 

57-86 

00-04 

40-86 

25 

2( 

22-83 

74-85 

25-41 

74-53 

22-22 

68-51 

13-40 

56-91 

4399-06 

39-87 

26 

27 

22-05 

74-04 

24-57 

73-67 

21-34 

67-60 

12-47 

55-96 

98-08 

38-87 

27 

28 

21-26 

73-22 

23-74 

72-81 

20-45 

66-69 

11-54 

55-00 

97-11 

37-87 

28 

21 

20-47 

72-41 

22-90 

71'95 

19-57 

65-78 

10-61 

54-05 

96-13 

36-87 

2!) 

30 

19-68 

71-60 

22-06 

71-09 

18-69 

64-88 

09-67 

53-09 

95-16 

35-87 

30 

(  *1 

18-89 

70-78 

21-22 

70-22 

17-80 

63-97 

08-74 

52-14 

94-18 

34-87 

31 

32 

1810 

69-97 

20-39 

69-36 

16-91 

63-Of 

07-81 

51-19 

93-20 

33-87 

32 

;  w 

17-31 

69-16 

19-55 

68'50 

16-03 

62-15 

06-88 

50-23 

92-22 

32-87 

.33 

34 

16-52 

68-34 

18-71 

67-64 

15-14 

61-24 

05-94 

49-27 

91-25 

31-87 

34 

ar 

15-73 

67-53 

17-87 

66'77 

14-26 

60-33 

05-01 

48-32 

90-27 

30-87 

35 

r)3( 

14-94 

66-71 

17-03 

65'91 

13-37 

59-42 

04-08 

47-36 

89-29 

29-87 

36 

(87 

14-15 

65-89 

16-19 

65'05 

12-4b 

58-51 

03-14 

46-41 

88-31 

28-87 

137 

(38 

13-35 

65-08 

15-35 

6418 

11-59 

57-60 

02-21 

45-45 

87-33 

27-87 

38 

'  3! 

12-56 

64-26 

14-51 

63-32 

10-70 

56-68 

01-28 

44-49 

86-35 

26-87 

39 

4( 

11-77 

63-44 

13-67 

62'45 

09-81 

55-77 

00-34 

43-53 

85-37 

25-86 

40 

»41 

10-98 

62-52 

12-82 

61*81 

08-93 

54-8f 

4499-40 

42-57 

84-39 

24-86 

41 

•  42 

10-18 

61-81 

11-98 

6072 

08-04 

53-95 

98-47 

41-62 

83-41 

23-86 

42 

)48 

09-39 

60-99 

11-14 

59'85 

07-15 

53-03 

97-53 

40-66 

82-42 

22-85 

43 

'•44 

08-59 

60-17 

10-30 

58'99 

06-26 

52-12 

96-59 

39-70 

81-44 

21-85 

44 

)45 

07-80 

59-3, 

09-45 

58-12 

05-36 

51-21 

95-66 

38-74 

80-46 

20-85 

45 

4( 

07-00 

58-53 

08-61 

57'25 

04-47 

50-29 

94-72 

37-78 

79-48 

19-84 

46 

<« 

06-21 

57-7 

07-76 

56'38 

03-58 

49-38 

93-78 

36-82 

78-49 

18-84 

47 

48 

05-4 

56-89 

06-92 

55'51 

02-69 

48-46 

92-84 

35-86 

77-51 

17-83 

48 

(48 

04-6 

56-07 

06-07 

54'65 

01-80 

47-55 

91-91 

34-89 

76-53 

16-82 

49 

5( 

03-8 

55-25 

OS'23 

53'78 

00-90 

46-61 

90-97 

33-93 

75-54 

15-82 

50 

51 

03-0 

54-43 

04-3 

52'91 

03-01 

45-71 

90-03 

32-97 

74-56 

14-81 

51 

/52 

02-2 

53-6 

03'54 

52'04 

4599-12 

44-80 

89-09 

32-01 

73-57 

13-80 

->2 

69 

01-4 

52-7 

02-69 

5117 

98-22 

43-88 

88-15 

31-04 

72-59 

12-80 

53 

M 

00-6 

51-9 

01'84 

50-30 

97-33 

42-iH 

87-21 

30-08 

71-60 

11-79 

54 

5 

4799-8 

61-1 

01-00 

49-42 

96-44 

42-04 

86-27 

29-12 

70-62 

10-78 

56 

<<> 

99-021    50-3 

00-15 

48'  55 

95-54 

41-13 

85-32 

28-15 

69-63 

09-77 

-><; 

6 

98-22     49-49 

4699-30 

47  '68 

94-64 

40-21 

84-38 

2719 

68-64 

08-76 

57 

)5 

97-42     48-6 

98-45 

46-81 

93-75 

3H-2J 

83-44 

26-22 

67<66 

07-75 

58 

)5 

96-62     47-8 

97-60 

45-94 

92-85 

38-37 

82-50 

25-26 

66-67 

06-74 

59 

jfl 

95-821    47-0 

96-75 

45-06 

91Tf 

37-  IF 

81  -5r 

21-29 

65-08 

05-73 

60 

J.    C.    SAL  A,    SAN    FRANCISCO 


T  ABLE.TF- 

Length  of  a  Degree  of  Longitude. 


>, 

39° 

400 

410 

42^ 

430 

440 

450 

460 

470 

480     '  ! 

chains. 

chains. 

;ha'.ns. 

lair.s. 

lains 

lains. 

cluh.s. 

wins. 

bains. 

aains.       > 

0 

4305.73 

44-47  4 

181-91 

18-06 

052-96 

986-62! 

5919-05 

850-28 

780-33 

709-22  0 

1 

04-72 

43-44 

80-85 

1C-U9 

51-87 

85-50 

17-91 

49-12 

79-15 

08-03  1 

•2 

03-71 

42-41 

79-80 

15-91 

50-77 

84-38 

16-78 

47-97 

77-98 

06-83  2 

i    3 

02-70 

41-37 

78-75 

14-84 

49-67 

83-27 

15-64 

46-81 

76-80 

05-63  3 

4 

01-69 

40-34 

7769 

13-76 

48-58 

82-15 

14-50 

45-65 

75-63 

04-44  4 

5 

00-68 

39-31 

7G-64 

12-69 

47-48 

81-03 

13-36 

44-50 

74-45 

03-24  5 

i 

4299-67 

38-27 

75-58 

11-61 

46-38 

79-91 

12-23 

43-34 

73-27 

02-05  6 

7 

98-65 

37-24 

74-52 

10-53 

45-28 

78-79 

11-09 

42-18 

72-09 

00-85  7 

8|    97-64 

36-20 

73-47 

09-46 

44-19 

77-68 

09-95 

41-02 

70-92 

699-65  8 

9     96-63 

35-17 

72-41 

08-38 

43-09 

76-56 

08-81 

39-86 

69-74 

98-46  9 

10 

95-61 

34-13 

71-36 

07-30 

41-99 

75-44 

07-67 

38-70 

68-56 

97-2610 

11 

94-60 

33-10 

70-30 

06-22 

40-89 

74-32 

06-53 

37-54 

67-38 

96-0611 

12 

93-59 

32-06 

69-24 

05-14 

39-79 

73-20 

05-39 

36-38 

66-20 

94-8612 

19 

92-57 

31-02 

68-18 

04-07 

38-69 

72-08 

04-25 

35-22 

65-02 

93-6613 

14 

91-56 

29-99 

67-12 

02-99 

37-59 

70-96 

03-11 

34-06 

63-84 

92-4614 

16 

90-54 

28-95 

66-07 

01-91 

36-49 

69-84 

01-97 

32-90 

62-66 

91-2615 

1C 

89-52 

27-91 

65-01 

00-83 

35-39 

68-72 

00-83 

31-74 

61-48 

90-06  16 

17 

88-51 

26-87 

63-95 

099-75 

34-29 

67-59 

899-69 

30-58 

60-3 

88-8617 

18 

87-49 

25-84 

62-89 

98-67 

33-19 

66-47 

98-54 

29-42 

59-1 

87-6618 

1] 

86-48 

24-80 

61-83 

97-58 

32-09 

65-35 

97-40 

28-26 

57-9 

86-4619 

21 

85-46 

23-76 

60-77 

96-50 

30-98 

64-23 

96-26 

27-09 

56-7 

85-2620 

21 

84-44 

22-72 

59-71 

95-42 

29-88 

63-11 

95-12 

25-93 

55-5 

84-0621 

21 

83-42 

21-68 

58-65 

94-34 

28-78 

61-98 

93-97 

24-77 

54-3 

82-8622 

21 

82-40 

20-64 

57-58 

93-26 

27-67 

60-86 

92-83 

23-60 

53-2 

81-6623 

24 

81-39 

19-60 

56-52 

92-17 

26-57 

59-73 

91-68 

22-44 

52-0 

80-4624 

2.' 

80-37 

18-56 

55-46 

91-09 

25-47 

58-61 

90-54 

21-28 

50-8 

79-2525 

2( 

79-35 

17-52 

54-40 

90-01 

24-36 

57-49 

89-4 

20-11 

49-6 

78-0526 

2" 

78-33 

16-48 

53-44 

88-92 

23-26 

56-36 

88-2 

18-9 

48-4 

76-8527 

77-31 

15-43 

52-27 

87-84 

22-15 

55-24 

87-1 

17-7 

47-2 

75-64  28 

2'. 

76-29 

14-39 

51-21 

86-7 

21-0 

54-11 

85-9 

16-6 

46-1 

74-44  29 

81 

75-27 

13-35 

50-1 

85-6 

19-94 

52-98 

84-8 

15-4 

44-9 

73-2430 

s: 

74-24 

12-31 

49-0 

84-5 

18-8 

51-86 

83-6 

14-2 

43-7 

72-03  31 

3- 

73-22 

11-26 

48-05 

83-5 

17-7 

50-7 

82-5 

13-1 

42-5 

70-83  32 

72-2 

10-2 

46-9 

82-4 

16-6 

49-6 

81-3 

11-9 

41-3 

69-6233 

;{- 

71-1 

09-1 

45-8 

81-3 

15-5 

48-4 

80-2 

10-7 

40-1 

68-4234 

:i 

70-1 

08-1 

44-8 

80-2 

14-4 

47-3 

79-0 

09-6 

38-9 

67-21  35 

1  :{ 

69-1 

07-0 

43-7 

79-1 

13-3 

46-2 

77-9 

08-4 

37-8 

66-01  30 

a 

68-1 

06-0 

42-6 

78-0 

12-1 

45-0 

76-7 

07-2 

36-6 

64-8037 

67-0 

05-0 

41-6J 

76-9 

11-0 

43-9 

75-6 

06-1 

35-4 

63-5938 

N  is 

66-0 

03-9 

40-5 

75-8 

09-9 

42-8 

74-4 

04-9 

34-2 

62-39  39 

4 

65-04 

02-9 

39-4 

74-8 

08-8 

41-7 

73-3 

03-7 

33-0 

611840 

64-0 

01-8 

33-4 

73-7 

07-7 

40-5 

72-1 

02-6 

31-8 

59-97  41 

62-9 

00-8 

37-3 

72-6 

06-6 

39-4 

71-0 

01-4 

30-6 

58-76  42  < 

61-9 

4199-7 

36-26 

71-5 

05-5 

38-3 

69-8 

00-2 

29-4 

57-56  43  ( 

60-9 
59-9 

98-7 
97-6 

35-2 
34-1 

70-4 
69-3 

04-4 
03-C 

37-1 
36-0 

68-7 
67-5 

3799-1 
97-9 

28-3 
27-1 

56-35  44 
55-1445 

58.8 

96-6 

35-0 

68-2 

02-2 

34-9 

66-4 

96-7 

25-9 

53-93  46 

57-8 
56-8 
55-8 

KAS 

95-5 
94-5 
93-4 

32-0 
30-9 
29-8 
28"' 

67-1 
66-0 
64-9 
63*5 

01-1 

3999-9 
98-8 
97-7 

33-7 
32-6 
31-5 
30-3 

65-2 
64-1 
62-9 
61-8 

95-5 
94-4 
93-2 
92-0 

24-7 
23-5 
22-3 
21-1 

52-7247 
51-51  48 
50-3049 
49-0950 

'. 

Oi    I 

53-7 

91-J 

27-7 

62-8 

96-6 

29-2 

60-6 

90-9 

19-9 

47-8851 

1 

I; 

52-7 
51-6 

49-f 
G     48-5 
>7l    47-r 
>8|     40- 
59     4.Vj 
501     44-4 

90-3 
89-2 
88-2 
87-1 
86-1 
85-0 
84-0 
82-9 
7     81-9 

26-6 
25-5 
24-5 
23-4 
22-3 
21-2 
20- 
19. 
18- 

61-7 
60-6 
59-5 
58-4 
57-3 
56-2 
55-1 
54-0 
52-9 

95-5 
94-4 
93-3 
92-1 
91-0 
89-9 
88-8 
87-7 
86-6 

28-1 
26-9 
25-8 
24-7 
23-5 
22-4 
21-3 
20-1 
19-0 

59-5 
68-3 
67-2 
66-0 
54-9 
53-7 
52-5 
51-4 
50-2 

89-7 
88-5 
87-3 
86-2 
85-0 
83-8 
82-6 
81-5 
80-3 

18-7 
17-5 
16-3 
15-1 
14-0 
12-8 
11-6 
10-4 
09-2 

46*67  52  ( 
45-46  53 
44-2554 
43-03  55 
41-8256 
40-61  5T 
39-4058 
38-1859 
30-9   60, 

^^/-^-"W-WN 

ILLUSTRATED   CATALOGUE   OP 


TABLE    HI. 


i            DIVERGENCY  OF  THE   PARALLEL  OF  LATITUDE  AND  THE 

<                                               PRIME  VERTICAL.                                             i 

Dist 

280 

300 

320 

340 

1  360 

380 

40° 

42  o 

440 

460 

480 

Dist 

mile 

chns 

chns 

chns 

chns 

!  chns 

chns 

chns 

chns 

chns 

chns 

chi 

mile 

1 

0.01 

0.01 

0.01 

0.01 

:  C 

.01 

0.01 

0. 

)1 

0.01 

0.01 

0.01 

0. 

n' 

1 

2 

0.02 

0.02 

0.03 

0.03 

i  0.03 

0.03 

0.03 

0.04 

0.04 

0.04 

0.04 

2 

3 

0.05 

0.05 

0.06 

0.06 

:  C 

.07 

0.07 

0. 

08 

0.08 

0.09 

0.09 

0.] 

o 

3 

4 

0.09 

0.09 

0.10 

0.11 

1  c 

.12 

0.13 

0. 

13 

0.14 

0.16 

0.17 

0. 

8 

4 

5 

0.13 

0.14 

0.16 

0.17 

:  0.18 

0.20 

0.21 

0.23 

0-24 

0.26 

0.28 

5 

6 

0.19 

0.21 

0.23 

0.24 

i  c 

.20 

0.28 

0. 

30 

0.33 

0.35 

0.37 

OJ. 

n 

6 

7 

0.26 

0.28 

0.31 

0.33 

i  0.36 

O.C8 

0.41 

0.44 

0.48 

0.51 

0.55 

7  ( 

8 

0.34 

0.37 

0.40 

0.43 

i  C 

47 

0.50 

0. 

•54 

0.58 

0.62 

0.67 

O.f 

i 

8  ( 

9 

0.43 

0.47 

0.51 

0-55 

i  0.59 

0.64 

0.68 

0.73 

0.79 

0.84 

0.90 

9 

10 

0.53 

0.58 

0.63 

0.68 

i  0 

.73 

0.78 

0. 

44 

0.90 

0.97 

1.04 

i.: 

1 

101 

11 

0.65 

0.70 

0.76 

0.82 

:  0 

.88 

0.95 

1. 

)2 

1.09 

1.17 

1.26 

i.e. 

-^ 

11 

12 

0.77 

0.83 

0.90 

0.97 

:  1.05 

1.13 

1.21 

1.30 

1.40 

1.50 

1.61 

12 

13 

090 

0.98 

1.06 

1.14 

i  1 

.23 

1-33 

1. 

42 

1.53 

1.64 

1.76 

l.l 

R 

13 

14 

1.05 

1.14 

1.23 

1.33 

i  1.43 

1.54 

1.65 

1.77 

1.90 

2.04 

2.19 

14 

15 

1.20 

1.30 

1.41 

1.52 

•  1 

.04 

1.76 

1. 

)0 

2.03 

2.18 

2.34 

2.£ 

1 

15 

16 

1.36 

1.48 

1.60 

1.73 

i  1.87 

2.01 

2.16 

2.32 

2.48 

2.66 

2.85 

16 

17 

1.54 

1.67 

1.81 

1.96 

i  2 

.11 

2.27 

2. 

44 

2.fil 

2.80 

3.00 

3.2 

9 

17 

18 

1.73 

1.88 

2.03 

2.19 

i  2.36 

2.54 

2.73 

2.93 

3.14 

3.37 

3.61 

18  ( 

19 

1.92 

2.09 

2.26 

2.44 

i  2 

.03 

2.83 

3. 

J4 

3.26 

3.50 

3.75 

4.0 

a 

19  (. 

20 

2.13 

2.32 

2.51 

2.71 

:  2.92 

3-14 

3.37 

3.02 

3.88 

4.16 

4.46 

20  ( 

21 

2.35 

2.55 

2.76 

2.98 

!    3 

.22 

3.46 

3. 

"2 

3.99 

4.28 

4.59 

4.9 

2 

21  ? 

22 

2.58 

2.80 

3.03 

3.28 

!  3 

.53 

3-80 

4. 

J8 

4.38 

4.69 

5.03 

5.4 

n 

22  r 

)   23 

2.82 

3.06 

3.32 

3.58 

3.86 

4.15 

4.46 

4.78 

5.13 

5.50 

5^90 

Am   ( 

23  f 

/   24 

3.07 

3.34 

3.61 

3-90 

4-20 

4.52 

4.85 

5.21 

5.59 

5.99 

6.42 

24 

;  25 

3.33 

3.62 

3.92 

4.23 

i  4 

.50 

4.90 

5. 

11 

5.65 

6.06 

6.50 

6.9 

7 

25 

26 

3.60 

3.91 

4.24 

4.57 

4.93 

5.30 

5.70 

6.11 

6.56 

7.03 

7.54 

26    > 

)   27 

3-89 

4.22 

4.57 

4.93 

5 

•32 

5.72 

6. 

14 

6.59 

7.07 

7.58 

8.1 

a 

27    ' 

)   28 

4.18 

4.54 

4.91 

5-31 

5.72 

6.15 

6.61 

7.09 

7.60 

8.15 

8.7-1 

28   > 

S   29 

4.48 

4.87 

5.27 

5.69 

6 

13 

6.60 

)9 

7.61 

8.16 

8.74 

9.3 

8 

29   > 

<   30 

4.80 

5.21 

5.64 

6.09 

6 

50 

7.06 

7. 

38 

8.14 

8.73 

9.36 

10.0 

A 

30  ) 

31 

5.12 

5.57 

6.02 

6.50 

7.01 

7.54 

8.10 

8.69 

9.32 

9.99 

10.79 

31  ) 

32 

5.46 

5.93 

6.42 

6.93 

7 

47 

8.03 

8L< 

Y3 

9.26 

9.93 

L0.65 

11.4 

9 

32  S 

33 

5.81 

6.31 

6.83 

7.37 

7.94' 

8.54 

9.18 

9.85 

10.56 

L1.32 

12.14 

33 

34 

6.16 

6.69 

7.25 

7.82 

8 

43 

9.07 

9.' 

'4 

10.45 

11.21 

L2.02 

12.8 

1 

34 

35 

6.53 

7.09 

7.63 

8.2D 

8-D3 

9.61 

10.32 

11.08 

11.88 

12.74 

13.66 

35  < 

36 

6.9J 

7.51 

8.12 

8.77 

9.45  10.16 

10.92 

11.72  12.57 

13.47 

14.45 

36 

i   TABLE  showing  the   Difference  of  Latitude  and  Departure  in    » 

running  80  chains, 

at  any  course  from  1  to  60  minutes. 

Min's 

Links 

.  Miu' 

s  Links.    Min's 

Links.    Min's 

Links. 

lin's  I 

inks.    A 

lin's 

Links.  J> 

1 

2i 

11 

25  f        21 

49          31 

72} 

41 

95f 

51 

119     ) 

2 

4;: 

12 

28 

22 

51}        32 

741 

42 

98 

52 

121}  S 

3 

7' 

13 

30}        23 

63f        33 

77 

43 

100J 

53 

123|  ( 

4 

9} 

14 

32f        24 

56          34 

79} 

44 

1028 

54 

126 

5 

Hf 

15 

35          1 

>5 

58}        35 

81f 

45 

105 

55 

128*  < 

6 

14 

16 

37}        i 

6 

60|        36 

84 

46 

107} 

56 

130f  < 

7 

16} 

17 

39?        27 

63          37 

86} 

47 

109i 

57 

133     ( 

8 

18 

42         1 

8 

65*        38 

88§ 

48 

112 

58 

135|  < 

9 

21  3 

19 

44}        29 

67f        39 

91 

49 

114} 

59 

137* 

'   10 

23} 

26       46  §        30 

70          40 

93} 

50 

L16f        60 

140    <J 

^ 

'-N- 

S~***~S^-/~**~/~^'-^ 

J.    C.    SALA,    SAN   FRANCISCO 


155 


TABLES. 


i                   TABLE  for  reducing  Chains  to  Feet,   and 
t                                          Feet  to  Chains. 

'Chains 
or 
^Links. 

Feet. 

Chains 
or 
Links. 

Feet. 

Chains 
or 
Links. 

Feet. 

Chaii 
or 
Links 

is 
Feet. 

fr- 

Chalp 
or 
Linfrs 

Feet.     ' 

'       1 

66 

21 

1386 

41 

2706 

61 

4026 

81 

5346 

<;    2 

132 

22 

1452 

42 

2772 

62 

4092 

5412 

3 

198 

23 

1518 

43 

2838 

63 

4158 

88 

5478 

4 

264 

24 

1584 

44 

2904 

64 

4224 

84 

5544 

5 

330 

25 

1650 

45 

2970 

65 

4290 

86 

5610 

6 

396 

26 

1716 

46 

3036 

66 

4356 

86 

5676 

7 

462 

27 

1782 

47 

3102 

67 

4422 

87 

5742 

8 

528 

28 

1848 

48 

3168 

68 

4488 

88 

5808 

9 

594 

29 

1914 

49 

3234 

69 

4554 

39 

5874 

10 

660 

30 

1980 

50 

3300 

70 

4620 

90 

5940 

11 

726 

31 

2046 

51 

3366 

71 

4686 

91 

6006     C 

12 

792 

32 

2112 

52 

3432 

72 

4752 

P2 

6072      ( 

13 

858 

33 

2178 

53 

3498 

73 

4818 

6138 

14 

924 

34 

2244 

54 

3564 

74 

4884 

94 

6204      s 

15 

990 

35 

2310 

55 

3630 

75 

4950 

9o 

627C     ( 

16 

1056 

36 

2376 

56 

3696 

76 

5016 

96 

633«     ( 

17 

1122 

37 

2442 

57 

3762 

77 

5082 

97 

6402     ( 

;  is 

1188 

38 

2508 

58 

3828 

78 

5148 

98 

6468     ( 

1      19 

1254 

39 

2574 

59 

3894 

79 

5214 

99 

6534     ( 

20 

1320 

40 

2640 

60 

3960 

80 

5280 

ibo 

6600 

TABLE  of  Acres  required  per  Mile,  and  per  100  Feet, 
for  different  widths. 

wxtth. 

Acres 

Acres 

width 

Acres 

Acres 

width. 

Acres 

Acres 

Feet. 

iK. 

per 
100  feet. 

Feet. 

per 
Mite. 

per 

100    eet. 

Feet. 

per 

Mile. 

per 
100  feet,    i 

~~1 

.121 

.002 

23           2.79 

.053 

45 

5.45 

'   .103 

2 

.242 

.005 

24 

2.91 

.055 

46 

5.58 

.106 

3 

.364 

.007 

24* 

3.00 

.057 

47 

5.70 

.108 

4 

.485 

.009 

25 

3.03 

.058 

48 

5.82 

•    .110 

5 

•606 

.011 

26 

3.15 

.060 

49 

5.94 

'    .112 

6 

.727 

.014 

27 

3.27 

.062 

49  i 

6.00 

.114 

'      7 

.848 

.016 

28 

3.39 

.064 

50 

6.06 

.115 

'      8 

.970 

.018 

29 

3.52 

.067 

51 

6.18 

.117 

81 

1.00 

.019 

30 

3.64 

.069 

52 

6.30 

.119 

9 

1.09 

.021 

31 

3.76 

.071 

53 

6.42 

.122     ) 

10 

1.21 

.023 

32 

,3.88 

.073 

54 

6.55 

.124 

11 

1.33 

.025 

33 

4.00    . 

.076 

55 

6.67 

.126     < 

12 

1.46 

.028 

34 

4.12 

.078 

56 

6.79 

.129     ( 

13 

1.58 

.030 

35 

4.24 

.080 

57 

6.91 

.131     ( 

14 

1.70 

.032 

36 

4.36 

.083 

57| 

7.00 

.133     ( 

15 

1.82 

.034 

37 

4.48 

.085 

58 

7.03 

.134     < 

16 

1.94 

.037 

38 

4.61 

.087 

59 

7.15 

.135     ( 

2.00 

.038 

39 

4.73 

.090 

60 

7;27 

.138     / 

17* 

2.06 

.039 

40. 

4.85 

.092 

61 

7.39 

.140 

18 

2:18 

.041 

41 

4.97 

.094 

62 

7.52 

.142     / 

i     19 

2.30 

.044 

5.00 

.095 

63 

7.64 

.145     ) 

20 

2.42 

.046 

42* 

5.09 

.096 

64 

7.76 

.147     > 

21 

2.55 

.048 

43 

5.21 

.099 

65 

7.88 

.149     > 

22 

2-67 

.051 

44 

5.33 

.101 

66 

8.00 

.151    ) 



156 


ILLUSTRATED   CATALOGUE   OF 


MISCELLANEOUS. 


APPROXIMATE  RULES  CONVENIENT  IN    PRACTICE. 

I.    FOR  CORRECTING  RANDOM  LINKS.* 

1.  Given  the  error  of  latitude  or  departure,  for  any  distance,  to  find 

the  error  of  the  course. 

RULE.— Three-sevenths  of  the  error  of  latitude  or  departure,  per  mile,  in  links, 
will  be  the  error  of  the  course,  in  minutes. 

EXAMPLE. 

What  is  the  error  of  the  course  for  an  error  of  210  links  of  latitude  or  departure, 
in  C  miles  ? 

Here  the  error,  per  mile,  is  35  links,  three-sevenths  of  which  is  15  minutes,  the 
error  required. 

2.  Given  the  error  of  the  course,  to  find  the  corresponding  error  of 

latitude  or  departure  Jor  any  distance. 

RULE — Seven-thirds  of  the  error  of  the  course,  in  minutes,  will  be  the  error  of 
latitude  or  departure,  per  mile,  in  links. 

EXAMPLE. 

What  is  the  error  of  latitude  or  departure,  in  6  miles,  for  an  error  of  15  minutes 
in  the  course? 

Here  seven  thirds  of  15  is  35  links,  the  error  per  mile,  or  210  links  in  6  miles,  the 
error  required. 

II.    FOR  RUNNING  A  PARALLEL  OF  LATITUDE^ 
Given  the  distance  run,  east  or  west,  on  a  great  circle,  to  find  the 

divergency  from  the  parallel  of  latitude. 

ROLE  —Multiply  the  square  of  the  distance  in  miles,  by  the  natural  tangent  of 
the  latitude,  and  the  product  wi-11  be  the  divergency,  in  links. 

EXAMPLE. 

After  running  6  miles,  east,  or  west,  on  the  arc  of  a  great  circle,  from  latitude  38 
degrees,  what  will  be  the  meridional  distance  south  of  the  parallel? 
Here  we  have  .781x62  =~  28  links,  the  divergency  required 

TRIGONOMETRICAL   SERIES 

A3'         A  5  AT 

Sin  A  —  A +    -     — « +  etc. 

2.3        2.3.4.5  2.3.4.5.6.7 

A2           A4  A6 

Cos  A  —  1 + +  etc. 

2            2.3.4  2.3.4  5.6 

A3         2A5         17A? 

Tan  A  —  A    +    —  +  +   +  etc 

3  3.5  32.5.7 

1         A        A3  2A5 

Cot  A  =• —  —  etc. 

A        3        32.5       33  5.7 

sin3  A        3  sin5  A        3.5  sin?  A 

Arc  A  —  sin  A  + + +  — +  etc. 

.     2.3  2.4.5  2.4.6.7 

1  1  1 

Arc  A=  tan  A  —  —  tan 3  A  +  — tan^A tan?A  +  etc. 

3  5  7 


*  This  approximation  is  true  to  the  nearest  minute  for  all  angles  up  to  3  deg. ; 
and  to  the  nearest  quarter  of  a  degree  for  all  angles  up  to  11 J  degrees. 

t  This  approximation  may  be  considered  practically  correct  for  any  distance  not 
exceeding  30  miles. 


J.    C.    SALA,    SAN    FRANCISCO 


sc  K  L  L  A  NEO  U  S 


)     Rules  for  Solving  all  Cases  of  Plane  Trigonometry. 

CASE  1. 

Given  all  the  Angles  and  One  Side,  to  find  the  other  Side. 
',       Kri.i:.—  As  sine  of  the  angle  opposite  the  given  side,  is  to  sine  of  the  angle 
-He  the  required  side,  so  is  the  given  side  lo  the  required  side. 

CASE    2. 

(  Given  two  tii</t<«  and  an  Angle  opposite  one  of  them,  to  And  the 
(  other  Angles  and  Side. 

KULK.— As  the  side  opposite  the  given  angle,  is  to  the  other  given  side,  so  is  sine 
(  of  the  angle  opposite  the  former,  to  sine  of  the  angle  opposite  the  latter.' 


CASE   3. 
Given  two  Sides  and  the  included  Angle,  to  find  the  other  Angles 

and  Side. 

RULE. — Subtract  the  given  angle  from  180  degrees  and  the  remainder  will  be  the 
um  of  the  two  unknown  angles ;  then  say,  as  the  sum  of  the  two  given  sides  is  to 


TABLE  FOR  RUNNING  ON  SLOPES, 

In  the  following  table  the  first  column  shows  the  angle,  the  second  the  number  of 
links  to  be  added  to  a  chain  on  the  slopes,  to  make  1  chain  horixontal  measurement. 


Angle.'  Cor.  in  links 

Angle. 

Cor.  in  links 

Angle. 

Cor.  in  links 

Angle. 

Cor.  in  links 

o 

o 

0 

o 

1 

0.24 

11 

1.88 

18 

5.14 

25 

10.54 

. 

0.28 

12 

2.24 

19 

5.76 

20 

11.26 

C> 

0.55 

13 

2.63 

21) 

6.42 

27 

12.24 

7 

0.70 

14 

3.06 

21 

7.11 

28             13.37 

8 

0.98 

15 

3.63 

22 

7.85 

29 

14.34 

1.24 

16      f        4.02 

23 

8.64 

30 

15.47 

10 

1,55 

17               4.56 

24 

9.47 

86 

22.07 

their  difference,  so  is  tangent  of  half  sum  of  unknown  angles,  to  tangent  of  half 
their  difference.  Add  this  half  difference  of  the  unknown  angles  to  their  half  sum 
for  the  angle  opposite  the  greater  side,  and  subtract  it  from  the  half  sum  lor  the 
angle  opposite  the  less  side. 

CASE   4. 
Given  the  Three  Sides  to  find  the  Angles. 

RULE— Upon  the  longest  side  let  fall  a  perpendicular  from  the  opposite  angle. 
This  perpendicular  will  divide  the  base  into  two  segments  and  the  triangle  into  two 
right-angled  triangles  ;  then  say,  as  the  given  base  is  to  the  sum  of  tire  two  other 
sides,  so  is  the  difference  ot'those  sides,  to  the  difference  of  the  segments  of  the 
base.  To  half  the  base  add  half  the  difference  of  the  segments  for  the  greater  seg- 
ment, and  subtract  it  from  half  the  base  for  the  less  side;  then  proceed  as  in  Case  2.  < 

Rn.K  *.— Add  together  the  arith.  comp.  of  the  logarithms  of  the  two  sidea,  con-    y 
taining  the  required  angle,  the  log.  of  thehalf  sum  of  the  three  sides  and  the  log. 
of  the  difference  of  the  half  sum  and  the  side  opposite  the  required  angle.    The 
half  sum  of  these  four  logarithms  will  be  the  logarithmic  cosine  of  half  the  required 
angle. 

FOR  FINDING  THE  DIAMETER  OF  A  TREE. 

j^u  K Annex  a  cipher  to  the  number  of  links  around  the  tree,  and  one  fourth 

of  the  result  will  be  the  diameter,  in  inches. 

EXAMPLE. 
What  is  the  diameter  of  a  tree  whose  circumference  is  16  links  ? 

Here  we  have  £  of  160  =  40  inches,  the  diameter  required. 


ILLUSTRATED    CATALOGUE   OF 


T  A  B  L  E  S. 

Position  of  the  Principal  Lines  of  the  United  States  Surveys  in  the  Stale  of  California. 
MONTE  DIABLO  Merid,,  Mt.Diablo.  Lat.  37°  52"  47",  Long.  121"  54'  49"  W. ; 


PARALLEL. 

Latitude. 

Distance. 

Miles 
0 
30 
60 
90 
120 
150 
180 
210 
240 
270 
284 
24 
48 
72 
96 
12  ' 
141 
168 
192 
216 
240 

Longitude      ' 
per  Kanget 

Converg.  • 

Chains.  ; 
0.00 
2.84     > 
2.88     \ 
2.93     <> 
2.97      < 
3.02     (' 
2.06     ( 
3.11      ( 
3.16     } 
3.21      - 
1.48     } 
2.25     > 
2.22     S 
2.19      ( 
2.17      ( 
2.14     ( 
2.11      ( 
2.09      ( 
2.06     ( 
2.03      k 
2.00      ( 

)  Monte  Diablo 

0          /       // 

37     52    47 

0         /        //        | 

0       0    35.2 
0       6    37.5    j 
0       6    3^.9 
0       6    42.4    , 
0       6    44.9 
0      6    47-5 
0      6    50.1 
0      6     52.8 
0       6    55.5 
0       6    58.3 
0       6    59.6 
0       6    33-4 
0       6    31.6 
0       6    29.8 
0       6    28.0 
0       6    26.3 
0       6     24-6 
0       6     22.9 
0       6    21.3 
0       6     19.7 
0      6    18.1 

)       I  Standard  Kor:'»  .... 
S      11 

38     18     53 
38    44     58 

(    111        "             " 

39     11       4 

(      V        "             "      '.'". 

i     39     37     10 
40      3     15 

40     29     21 

vis    ?.      »  ::: 

J>    IX        "             "      .... 
'  Oregon  Boundary  
)         I  Standard  So-ith   .  .  . 
)       11 
J      111 

vi  '  ^    ^  ::: 

40     55     26 
i     41     21     31 
41     47     54 
42      0      0 
37     31     54 
37     11       1 
36     50      8 
36     29     14 
36      8     21 
!     35    47     28 

VII 
VIII          "            "       ... 
IX          "            "... 
X          "            "      ... 

35     26     35 
...       35      5    41 
....    .34     44     48 
....       34     23     55 

HUMBOLDT  MERID., 

Mt.  Pierce,    Lat.  40°  24'  56",  Long.l24°07'  03"  \V.    J 

PARALLEL. 

Latitude. 

Dio'.ance. 

Longitude 
per  ilange. 

Converg. 

Mount  Pierce 

O        /     r  r 
....      40     24     56 

Miles. 
0 
30 
60 
90 
109.32 

24 

r      /      // 

0       6    49.6 
0       6     52.3 
0       6     55.0 
0       6     57.9 
0       6    5D.fi 

0       6     47.5 

Chains.  { 
0.00      r 

3.15      / 
3.20      ) 
2.09      ) 
Diverg,  / 
2.48      ( 

1  Standard  North  
(*   11         " 

40     51       1 
....      41     17       6 

41     43     12 

1     42       0      0 

)l  Standard  South  

...      40       4       4 

)  SAN  BERNARDINO  Merid..  Mt.San  Bern.  I 

S 

<                  PARALLEL.                        Latitude. 

at.  34°  07 
Distance. 

'  25",  Long.  116°56'W.  ( 
/ 

Longitude 

per  Ilange. 

Converg.  x 
1 

;  Mount  San  Bernardino  .  .  . 
)     I  Standard  North  
11         -            "        
Ill         "             "        

>rv  

V         "             "        
VI 

o       /    // 
34       7     25 
34     33     32 
34     59     39 
35     25    46 
35    51     53 
i     36     18       0 
36     44      6 

Miles. 
0 
30 
60 
90 
120 
150 
180 

24 

48 
72 
96 
120 

o      /      // 
0       6     16.9 
0      6     18.8 
0       6     20.8 
0      6     22.8 
0       6     24.9 
0      6     27.1 
0      6     29.2 

0       6     15.1 
0       6     13.8 
0       6     1?.! 
0      6     10.9 
0       6      9.5 

Clriirs.  ( 
0.0(1      | 
2.47      , 
2.51 
2.56      ; 
2.60      ) 
2.64      ) 
2.68      S 
Diverg.  ) 
1.95 
1.93 
1.90 
J.87 
1.85 

1  Standard  South  
11          "                "       
HI        "                "       

xv    -      ••  -: 

33     46     31 
33     25     38 
33       4    34 
32    43     50 
32    22     56 

J.    C.    SAL.A,    SAN    FRANCISCO 


TABLES 


159 


POSITION  or  THE  PRINCIPAL  LINES  or  THE  UNITED  STATES  SUHVKYS  IN  THE 

STATE  OF  NEVADA. 

The  principal  Huso  and  Standard  Parallels  in  this  State  are  precisely  the  same 
as  t  hose  of  California.  All  the  townships  are  numbered  from  the  Monte  Diablo 
meridian  and  bus,  line.  The  Fourth  Standard  Parallel  base  line  commences  at 
the  California  and  Nevada  State  lines,  run  by  A.  W.  von  Schmidt,  at  the  line 
between  Ranges  17  and  IS,  aud  extends  to  the  Utah  boundary  line  in 
Range  70. 

There  are  four  Guide  Meridians,  viz.: 

CABSON   GUIDE   MERIDIAN,  running  north  from  the  Fourth  Standard 
North,  between  Ranges 20  and  21  E.  M.  D.  M. 

HUMBOLDT  RIVER  GUIDE  MERIDIAN,  running  north  from  the  Fourth 
Standard  North,  between  ranges  35  and  36  E.  M.  D.  M. 

REESE  RIVER  GUIDE  MERIDIAN,  running  south  from  the  Fourth  Stan- 
dard North,  between  Ranges  42  and  43  E.  M.  D.  M. 

P.UBY  VALLEY  GUIDE  MERIDIAN,  running  N.  and  S.  from  the  Fourth  ' 
Standard  Parallel  North,  between  Ranges  55  and  56  of  the  Monte  Diablo  ' 
meridian. 


(                  Position  of  the   Principal  Lines  of  the  United  States  Surveys  in                ( 
UTAH                                                                             $ 
Initial  Point,  Salt  Lake  Base  and  Meridian.                                                               (' 
Latitude,  40°  46'  08"  North;   Longitude  111°  53'  47"  West.     ( 

Surveys  North  of  the  Base  Line.                               \ 

Parallel. 

Latitude. 

Distance 

Longitude, 
per  Range. 

i* 
ConvergJ  ^ 

Initial  Point  

o     /    // 

40    46    08 
41    07    00 
41     27    52 
41    48    44 
42    00    00 

Miles. 
0 
24 
48 
72 
84.95 

o      /     // 
0      6    51.8 
0      6    53.9 
0      6    56.1 
0      6    58.4 
0      6    59.6 

Chains,      / 
0   0       / 
2.51        ' 
2.54 
2.58 
1.40 

I  Standard  North  
II        "             •'      
(    III        "              "     
(    Oregon  Line      

Surveys  South  of  the  Base  Line. 

Initial  Point 

40    46    08 
40    20    03 
39    53    57 
39    27    51 
39    01    46 
38    35    40 
38    09    34 
37    43    28 
37    17    22 
37    00    00 

Miles. 
0 
30 
60 
90 
120 
150 
180 
210 
240 
259.95 

0       /       ff 
0      6    61.8 
0      6    49.1 
0      6    45.6 
0      6    440 
0      6    41.5 
0      G    39.1 
0      6    36.7 
0      6    34.3 
0      6    32.1 
0      6    30.1 

Chains      I 
0   0      . 
3.0&       ' 
3.C5 
2.99      % 
2.95 
2.91 
2.86 
2.8JJ       . 
2.78      '• 
2.31 

I  Standard  South..., 
II 
III                      '•      ..   . 
IV                      "      . 
V 
VI                     "      . 
VII                     "      ... 
VIII                     "      .... 
)    Arizona  Line  

COLORADO  BASE  LINE, 

Latitude  of  Initial  Point,  33  deg.  51  mln. ;. . . .Longitude,  114  deg.  22  min.          i 
Meridian  runs  north  12  miles  to  Lat.  34  deg.  1  min.  27  sec. 

Convergency,  0,97  chains.    .' 


i6o 


ILLUSTRATED    CATALOGUE    OF 


T  A  JJ  L  E  S 


^      POSITION  OF  THE  PRINCIPAL  LINES  OE  THE  U.  S.  Suiiv.  iv  ARIZONA  'PER. 
)  Initial  Point,  junct.  of  Salt  &  Gila  rivers.  Lat.  33°  22"  57", Long.  112°  15"  46" 
Surveys  north,  of  Gila  and  Salt  River  Rise  Line. 


•) 

Parallel. 

Latitude. 

Distance. 

Longitn  de 
per  K:mgc'. 

Converg. 

Chuins. 
0    0 
1.92 
1.95 
1.97 
2.00 
2.02 
2.05 
2.08 
2.10 
2.13 
2.16 
0.85 

Chains. 
0    0 
2-37 
2.33       ( 
2.29       , 
2.26       , 

) 
)  Initial  Point 

o      /     // 

33     22    57 
33    43     51 
34    04     45 
1     34     25     38 
34    46     32 
35     07     25 
35    28     18 
35     49     12 
36    10    05 
36    30     58 
36     51     52 
37    00    00 

h  of  Gila  and 
o     /    // 
33     22     57 
32    56    50 
32     30    42 
32    04     35 
31    38    27 

Allies. 
0 
24 
48 
72 
96 
120 
144 
168 
192 
210 
240 
249.35 

Salt  Rii 

Miles. 
0 
30 
60 
90 
120 

o      /      /  / 
0       6     13.6 
0       6     15.1 

o     6    K;.I; 

0       6     18.2 
0       6    19.8 
0       6    21.4 
0       6     2S.O 
0       6     24.7 
0       6     26.4 
0       6     28.1 
0       6     29.9 
0       6     30.6 

~er  Base  Line. 
<j      r     // 

0       6     13.6 
0       6     11.8 
0      6    10.0 
0      6      8.2 
0       6       6.5 

>          1  Standard  IS  orth 
11         "             "      .     . 
.      Ill         "             "      . 

^   ::     ::  

VI 

\'ii 
via 

IX         "             "... 
X 

North  Boundary  . 

Surveys  sout 
Initial  Point  

I  Standard  South... 

'II         "            "      
Ill 

IV         "             "      

Initial  Point  of  Williametta  MeridLn,  WASHINGTON 
Base  Line,  Lat.  45°  31  '  13"  North,  Long.  122°  CO'  2u"  W. 

Parallel. 

Latitude.       |  Distance. 

Longitude 
per  Range. 

( 
Converg.    ( 

Chuins. 
00       < 
2.96       ( 
3.00 
3.04 
3.07       ) 
3.11       ) 
3.15       ) 
3.19       ) 
3.23       S 
3.27       S 
3.30 

1  Initial  Point    

o      /     // 
45     31     13 
45     52     04 
46     12     55 
46     33    46 
4<J     54     37 
47     15     28 
47     36     19 
47     57     09 
48     18    00 
48    38     51 
48     59     41 

Mlies. 
0 
24 
48 
72 
96 
120 
144 
168 
192 
216 
240 

0          /       // 

0      7     25.0 
0       7     27.7 
0       7     30.6 
0       7     33.4 
0       7     36.3 
0       7     39.3 
0       7     42.4 
0       7     45.4 
0       7     48.6 
0      7     51.8 
0       7     55.1 

I  Standard  North  
11 
HI        "              '      .   ... 
IV        "              '      .    .. 
V         "             '      
VI 
VII         "               •       
VIII         "              '      .    ... 
IX        "             '      
X        "              '      

Position  of  the  Principal  Lines  of  the  U.S.  Surveys  in  MONTANA 
Initial  Point,  intersec.  prin.  base  &  mer.,  lat.  45°46'27  N".  ;  Long.  111°27'  11'  'W 

Parallel. 

Latitude.       'Distance 

Longitude 
per  Range. 

Converg.   ( 

Principal  Base  
1  Standard  North  

\£ 

>  ';    ."     ::  ::  ::: 

VI 
VII         "             "      

;        I  Standard  South..., 
}       II 

45     4(J     27 
46     07     15 
46     28    03 
46     48    51 
47     09     39 
47     30     27 
47     51     13 
48     12     03 

45     20     27 
44     54     27     i 

Miles. 
0 
24 
48 
72 
96 
120 
144 
168 

30 

f-0       1 

0       7     27.8 
0       7     28.2 
0       7     28.5 
0       7     28.8 
0       7     29.2 
0       7     29.6 
0       7     29.9 
0       7     30.3 

0       7     27.3 
0       7     27.8 

Chains. 
00       / 
3.01       ) 
3.03       (. 
3.06       S 
3.11       ( 
3.15 
3.19 
3.22       ' 
Diverg.     ' 
3.71       < 
3.67       ( 

J.    C.    SALA,    SAN    FRANCISCO 


161 


T  A  B  L  K  S 


POSITION-   UK  TIIK  PRINCIPAL   LINES  OK    THE  U.  S.  SUKVEYS  IN  THE 

STATE  OF  OREGON. 
|   Initial  Point,  intersection  of  Willamette  meridian  and  baseline, 

Lat.  45° 31'  13"  North;   Long.  122° 30'  26"  West, 


Surveys  north  of  the  Willamette  Base  Line. 


Parallel 

Latitude. 

Distance 

Longitude 
per  Range. 

Converg. 

Wiihunrtt,-  Base  Line..... 
1  Mamlarti  Noitli     . 

;    ii    ••      -     .. 

o      /     // 
45    31     13 
45    52    04 
46    07    42 

Miles. 
0 
24 
42 

o      /     // 
0      7    25.0 
0      7    27.7 
0      7    29.8 

Chains. 
0    0 
2.90 
2.25 

Surveys  south  of  the  Willamette  Base  Line. 


0      >     "          MHes. 

/ 

"        Chain* 

Willamette  Base  Line    ... 

45    31     13 

0 

0 

7 

25.0 

0    0 

1  Standard  South.... 

45    05    09 

30 

0 

7 

21.6 

3.62 

II        "                "     .   ... 

44     39     03 

60 

0 

7 

18.3 

3.59 

Ill 

44     23     2C 

78 

0 

7 

16.3 

2.15 

IV 

43     57     22 

108 

0 

7 

13.1 

3.51 

v       ••         - 

43     36     30 

132 

o 

7 

10.6 

2.76 

vi       •           ••     .  ... 

43     10     26     i     162 

0 

7 

07.7 

3.41 

Vll 

42    44     21 

192 

0 

7 

04.6 

3.38 

VII  1 

42     28     42 

210            0 

7 

02.8 

2.00 

IX 

42     07     50     1     234       i     0 

7 

00.4 

2.63 

North  Bound,  of  Calif  'a.,  j 

42    00    00 

243       !     0 

<; 

59.5 

0.99 

162 


ILLUSTRATED   CATALOGUE   OF 


rr  A  H  L  E  s . 


TABLES  OF  GRADES, 

Per  Mile  and  per  100  Feet,  measured  horizontally  and  corresponding  to  different 
Angles  of  Elevation. 


1  -  • 

L, 

Feet 

Feet 

Feet  Feet 

Feet 

Feet 

Feet 

Feet  ( 

per 
mile. 

per 
100  ft. 

o  / 

per 
mile. 

per 
100  ft. 

0   / 

per 
mile. 

per 
100  ft. 

0   / 

per 

mile. 

1  ir'ft  '' 
'( 

1. 

0.01894 

0  18 

27.64 

0.5237 

54. 

1.02273 

81. 

1.53409; 

U  i 

1.636 

0.02091 

28. 

0.53030 

55. 

1.04167 

0  53 

81.40 

1.5419  ) 

t 

2. 

0.03788 

29. 

0.54924 

0  36 

55.30 

1.0472 

82. 

1.55303S 

< 

3. 

0.05682 

0  19 

29.17 

0.5528 

56. 

1.06061 

0  54 

82.94 

1.5710  ( 

(  0  2 

3.072 

0.0582 

30. 

0.56818 

0  37 

56.83 

1.0763 

83. 

L57197\ 

4. 

0.0757( 

0  20 

30.72 

0.5818 

57. 

1.07955 

84. 

1.5909K 

c  0  3 

4.608 

0.0873 

31. 

0.58712 

58. 

1.09848 

0  55 

84.47 

1.6000  ( 

5. 

0.09470 

32. 

0.6060( 

0  38 

58.37 

1.1054 

85. 

1.60985Y 

S 

6. 

0.11364 

0  21 

32.26 

0.6109 

59. 

1.11742 

86. 

1.62879( 

0  4 

6.144 

0.1164 

33. 

0.62501 

0  39 

59.90 

I.lo45 

0  56 

86.01 

1.0291  ) 

7. 

0.13258 

0  22 

83.86 

0.6400 

60. 

1.13636 

87. 

1.64773) 

0  5 

7.680 

0.1455 

31. 

0.64394 

61- 

1.15530 

0  57 

87.54 

1.6583  ) 

) 

8. 

0.15152 

35. 

0.66288 

0  40 

61.44 

1.1636 

88. 

1.66666) 

9. 

0.17045 

0  23 

35.33 

0.6691 

62. 

1.17424 

89. 

1.68561) 

S  0  6 

9.216 

0.1746 

36. 

0.68182 

0  41 

62.97 

1.1927 

0  58 

89.08 

1.6873  ) 

? 

10. 

0.18939 

0  24 

36.86 

0.6982 

63. 

1.19318 

90. 

1.70456J 

0  7 

10.75 

0.2037 

37. 

0.70076 

64. 

1.21212 

0  59 

90.62 

1  7164  S 

) 

11. 

0.20833 

38. 

).71970 

0  42 

64.51 

1.2218 

91. 

1.72348) 

12. 

0.22727 

0  25 

38.40 

0.7273 

65. 

1.2310f 

92. 

1.74242) 

)o  8 

12.29 

0.2328 

39. 

0.73864 

66. 

1.25000 

1  0 

92.16 

1.7455  ( 

? 

13. 

0.24621 

0  26 

39.94 

0.7564 

0  43 

66.04 

1.2509 

93.   1.76186S 

0  9 

13.82 

0.2619 

40. 

).75758 

67. 

1.26894 

94. 

1.78030( 

/ 

14. 

0.26515 

41. 

).77652 

0  44 

67.57 

1.2800 

95. 

1.  79924  ( 

r, 

15. 

0.28409 

0  27 

41.47 

0.7855 

68. 

1.28788 

1  2 

95.23 

1.8038  f 

0  10 

15.36 

0.2909 

42. 

0.79545 

69. 

1.30682 

96. 

1.81818? 

/ 

16. 

0.30303 

43. 

0.81439 

0  45 

69.11 

1.3090 

97. 

1.83712? 

>  0  11 

16.90 

0.3200 

0  28 

43.01 

3.8146 

70. 

1.32576 

J8. 

1.85606? 

17. 

0.32197 

44. 

0.83333 

0  46 

70.64 

1.3381 

1  4 

J8.30 

1.8620  ) 

( 

18. 

0.34091 

0  29 

44.54 

0.8436 

71. 

1.34470 

99. 

1.87500/ 

•,  0  12 

18.43 

J.3491 

15. 

X8522'3 

72. 

1.36364 

100. 

1.89394) 

' 

19. 

13598-) 

46. 

J.87121 

0  47 

72.18 

1.3672 

101. 

1.91288) 

;  0  13 

19.90 

0.3782 

0  30 

16.08 

0.8727 

73. 

1.38258 

1  06 

101.4 

1.9202  ) 

\ 

20.   10.37879 

47. 

189015 

0  48 

73.72 

1.3963 

102. 

1.93182) 

\ 

21.   0.3J773 

0  31 

47.62 

0.9018 

74. 

1.40152 

103. 

1.95076) 

(  0  14 

21.50  0.4073 

48. 

0.90909 

75. 

1.42045 

104. 

1.96969) 

22.   0.41667 

49. 

0.92803 

0  49 

75.26 

1.4254 

147. 

2.78409S 

S 

23. 

0.43561 

0  32 

49.16 

).9309 

76. 

1.43939 

1  36 

147.4 

2.7932  ( 

(  0  15 

23.0  i 

J.4J04 

50. 

).94697 

0  50 

76.80 

1.4545 

148. 

2.80308C 

24. 

0.45455 

0  33 

50.69 

0.9600 

77. 

..45833 

149. 

2.82197( 

j  0  10 

J4.58 

0.4655 

51. 

0.96591 

78. 

1.47727 

150. 

2.8409K 

25. 

0.47348 

52. 

0.98485 

0  51 

78.33 

1.4837 

1  38 

150.5 

2.8514  ? 

26. 

0.49242 

0  34 

52.23 

0.9891 

79. 

1.49621 

151. 

2.85985( 

0  17 

26.11 

0.4946 

53. 

1.00379 

0  52 

79.87 

1.5128 

152. 

2.87879? 

27. 

0.51136 

0  35 

53.76 

1.0182 

80. 

1.51515 

1  40 

153.6 

2.90P?  ? 

J.    C.    SALA,    SAN    FRANCISCO 


I63 


TABLE. 


)  TABLE  OF 

UADII,  MIDDLE  OKDINATES,  &c.,  OF  CURVES.  \ 

S  CHORD  100  FKKT. 

.  IT  The  Tun^ntia]  A=«Ic  is  always  one-half  of  the  Angle  of  DcflucMon. 


Deflw 

>       R:ulit 
III  fi-i-t 

Deflec. 
distance 

in  ft. 

Tunj 
,     dist 

in  for 

'.     Mid 
Ordi 

.       Aig 
Defle 

(.'       liadii    :'  Defle 
in  feet.  ;'    dist 
•  in  fee 

c.     Tang 
dist 
t.    in  fee 

Mid 

Ordi  i. 

r 

o    / 

~ 



\ 

143775 
171887 
86944 
67296 
42972 

.023 
.058 
.116 
.174 
.232 

.'114 
.029 
.058 
.087 
.116 

.004 
.008 
.014 
.022 
.028 

2     ( 

••  in 

"  18 
"  24 
"  30 

2729 

2604 
2491 
2387 
2292 

!    3.66J 
i    3.8LL 
:    4.014 
:    4.188 
i    4.363 

1.83i 

1.9m 

2.007 
2.094 
2.182 

J80  ( 
.502 
.523 
.545 

\ 

14 

H 

:ii:iTK 
28648 
24666 
21485 

.291 
.349 

.407 

.465 

.145 
.174 
.203 
.232 

.036 
.043 
.050 
.058 

"  C6 

"48 
"  54 

2204 
2122 
2046 
1976 

:    4.538 
:'    4.712 
I    4.886 

;     5.060 

2.269 
2.356 
2.443 
2.530 

.567 
.589 
.611 
.632 

18 

19098 

.52'{ 

.261 

.065 

3    0 

1910 

•    P.  235 

2.618 

.651 

20 

17189 

.581          .±M 

.073 

"  15 

176J 

I    5.C66 

2.8C6 

.710 

2! 

15C27           .639         .:i!9 

.080 

"  C-0 

1637 

i    C.108 

3.054 

.764  ( 

24 

14:.  _'l         .,-,1,7        .:!4K 

.087 

"  45 

1528 

3.272 

.818  ) 

2) 

13222 

.756 

.378 

.095 

4     0 

1433 

i    0.980 

3.490 

.873  ( 

28 

12278          .:<n 

.407 

.102 

1  "  15 

1E48 

:'    7.116 

3.708 

.927  ( 

:ii 

111.  v.i           .872 

.436 

.109 

"30 

1274 

:'    7.553 

3.927 

.981  ( 

32 

10743 

.930 

.465 

.116 

"45 

1207 

i    8.289 

4.145 

036  ) 

34 

10111 

.988 

.494 

.123 

5    0 

1146 

i    8.722 

4.361 

091  ( 

86 

9649 

1.046 

.523 

.131 

"  15 

1092 

;    9.159 

4.579 

146  C 

9046 

1.104 

.552 

.128 

"  30      1042 

:    9.595 

4.798 

200  f 

40 

8694 

1.162 

.581 

.145 

"45 

996.8 

i  10.03 

5.015  ,  1.255  ? 

42 

8185         1.221 

.610 

.152 

6     0 

955.4 

i  10.47 

5.235     1.30!)  ( 

44 

7814 

1.279 

.639 

.159 

"  15 

917.0 

:  lO.yO        5.450  1  1.:-fi4  C 

46 

7474 

1.137 

.668 

167 

"  CO 

882.0 

:  11-34 

5.070      1  47  <>  ( 

48 

7162 

1.395 

.697 

174 

"  45 

849.3 

;  11-78 

5.890 

1.473 

50 

6876 

1.453 

.726 

182 

7     0 

819.0 

i  12.21 

6.105 

1.528  < 

6611 

1.511 

.755 

189 

"15 

790.8 

!  12.64 

6.320 

1.582 

54 

6367 

1.569 

.784 

197 

"  30 

764.5 

i  13.08 

6.540 

1.6£7 

.;    56 

6139 

1.627 

.813 

204 

"45 

739.9 

i  13.51 

6.755 

1.692 

58 

5928 

1.685 

.842  1  .211 

8    0 

716.8 

i  13.95 

6.975 

1.746 

1     0 

5730 

1.745 

.872      .218 

"15 

695.1 

i  14.38         7.190 

1.801  < 

••     4 

5372     i    1.860 

.930 

.232 

"  30 

674.6 

:  14.81         7.405 

1.8C.3 

"     8 

5056         1.976        .988 

.246 

"45 

655.5 

:  15.25 

7.625 

1.910 

'  12 

4775         2.094     i  1.047 

.261 

9     0 

637.3 

i  15.68 

7.840 

1.965  < 

•   16 

4524         2.210     i  1.105 

.275 

"  15        620.2 

i  16.12 

8.960 

2.019  ( 

'  20 

4298 

2.326     :  1.163 

.290 

"  30        603.8 

:  16.55 

8.275 

2.074  ( 

"  24 

4093 

2.443     ;  1.221 

306 

"  45        588.4 

i  16.99 

8.495 

1.128  ( 

'  28 

3907         2.559     i  1.279      .320 

10    0        573.7 

•'  17.43         8.715     ; 

>.183  ( 

'  32 

3737         2.676     i  1.338      .334 

"  15        559.7 

17.87 

8.935     . 

"  36 

3581         2.793     j  1.396 

349 

"  30        546.4 

18.30 

9.150     <. 

'.2D2  ? 

I  "   40 

3438         2.908     \  1.454 

S64 

"  45        533.8 

18.73 

9.365     i 

».347  ? 

„  44 

3306 

3.025     i  1.512      . 

378 

11     0        521.7 

19.17 

9.585     J 

•401  S 

"  48 

3183 

3.141     i  l.~70      . 

393 

"  15        510.1 

19.61 

D.805     2 

.456  (, 

"  52 

3069 

3.258     i  1.629      . 

407 

"  30  '•     499.1 

20.05       1 

0.03       1 

.511  ( 

"  56 

2964 

3.374     :  1.687      . 

422 

"  45  '•     488.5 

20.50       1 

0.25       2 

.566  ( 

;  2    0 

2865 

3.490     :  1.745      . 

436       ] 

2     0  i     4  78.U 

20.94       1 

0.47       2 

.620  ( 

( 

( 

164 


ILLUSTRATED    CATALOGUE    OF 


TABLE. 
TEMPERATURE  OF  BOILING  WATER 

Corresponding  to  the  Height  of  Barometer  and  Altitude  above  Sea  Level, 


Thermo. 

Baro. 

Alti. 

Thermo. 

Baro,    Alti. 

Thermo. 

Baro. 

Alti.  > 

Deg. 

inch. 

feoi  . 

fi££ 

inch.    feet. 

I)  eg 

inch 

feet. 

184.0 

16.79 

15221 

IMfl 

20.82    9579 

204.6 

25.59 

4169 

.2 

16.86 

15112 

.2 

20.91    9466 

.2 

25.70 

4057 

>    .4 

16.93 

15003 

A 

21.00    9353 

.4 

25.88 

3945 

.6 

17.00 

14895 

.6 

21.09    9241 

.0 

25.91 

3344  } 

>    .8 

17.08 

14772 

.8 

21.18    9130 

.H 

26.01 

3742  / 

185.0 

17.16 

14649 

195.0 

21.26  ,  9031 

205.0 

26.11 

3642  ) 

.2 

17.23 

14543 

.2 

21.35    8920 

.2 

26.22 

3532  S 

.4 

17.31 

14421 

.4 

21.44    8810 

.4 

26.33 

3422  5 

.6 

17.38 

14315 

.6 

21.53    8700 

.6 

26.43 

3322  ( 

.8 

17.46 

14195 

.9 

21-62 

8590 

.8 

26.54 

3213  ( 

186.0 

17.54 

14075 

196.0 

21.71 

8481 

206.0 

26.64 

3115  (* 

)    '2 

17.62 

13956 

.2 

21.81 

8361 

.2 

26.75 

3007  ? 

17.70 

13837 

.4 

21.90    8253 

.4 

26.86 

2899 

f    *6 

17.78 

13718 

.6 

21-99  !  8145 

•6 

26.97 

2792  ) 

.8 

17.86 

13601 

.8 

22.08    8038 

.8 

27.08 

2685  ; 

187.0 

17.93 

13498 

197.0 

22.17    7932 

207.0 

27.18 

2589  S 

.2 

18.00 

13396 

.2 

22.27    7814 

.2 

27.29 

2483  ( 

.4   18.08 

13280 

.4 

22.36    7708 

.4 

27.40 

2377  ( 

.6   18.16 

13164 

.6 

22.45    7602 

.6 

27.51 

2272  ( 

\    .8   18.24 

13049 

.8 

22.54  .  7498 

.8 

27.62 

2167  ( 

<*  188.0 

18.32 

12934 

isao 

22.64    7381 

208.0 

27.73 

2063  <> 

}    -2   18.40 

12820 

.'2 

22.74    7266 

.2 

27.84 

1959  / 

-.4   18.48 

12706 

.4 

22.84  ;  7151 

A 

27.95 

1856  ( 

.6  ;  18.56 

12593 

.6 

22.93  i  7048 

.6 

28.06 

1753  ( 

,;    .8   18.64 

12480 

.8 

23.02 

6945 

.8 

28.17 

1650  ( 

)  189.0 

18.72 

12367 

19:  o 

23.11 

6843 

209.0 

28-29 

1539  ) 

.2 

18.80 

12256 

.2 

23.21  j  6729 

.2 

28-40 

1437  ) 

)    .4   18.88 

12144 

.4 

23.31 

6617 

A 

28.51 

1336  S 

)    .6   18.96 

12033 

.6 

23.40 

6516 

.6 

28.62 

1235  v 

)    .8 

19.04 

11923 

.8 

23.49 

6415 

.8 

28.73 

j 

1134  C 

190.0   19.13 

11799 

200.0 

23.59 

6304 

210.0 

1  28.85 

1025  ( 

.2  I  19.21 

11690 

.2 

23.69 

6193 

.2 

28.97 

910  ( 

.4   19.29 

11581 

A 

23.79 

6082 

.4 

29.09 

808  < 

.6   19.37 

11472 

.6 

23.89 

5972 

.6 

29.20 

709  C 

.8   19.45 

11364 

.8 

23.98 

5874 

.8 

29.31 

610  ? 

191.0   19.54 

11243 

201.T 

24.08 

5764 

211.0 

29.42 

512  ) 

.2   19.C2 

11136 

.2 

24.18 

5656 

.2 

29.54 

405  ) 

.4   19.70   11029 

.4 

24.28 

5547 

.4 

29.65 

308  ) 

)    .6   19.78  i  10923 

.6 

24.38 

5440 

.6 

29.77 

202  S 

S    .8   19.87   1080* 

.8 

24.48 

6332 

.8 

29.88 

105  J) 

\  192.0   19.96 

10685 

202.0 

24.58 

5225 

212.0 

30.00 

sea  level.  ( 

.2   20.05 

10567 

.2 

24.68 

5119 

below 

se  • 

level,  ( 

.4   20.14 

10450 

.4 

24.78 

5013 

.2 

30.12 

-  104  ( 

.6   20.22 

10346 

.6 

24.88 

4907 

.4 

30.24 

-  206  ( 

.8  j  20.31 

10230 

'8 

24.98 

4802 

.6 

;  30.35 

--  304  ( 

.8 

30-47 

-  405  ) 

193.0   20.39 

10127 

203.0 

25.08 

4697 

.2  !  20.48   10011 

•2 

25.18 

4593 

213.0 

30.59 

-  512 

.4 

20.57    9896 

.4 

25.28 

4489 

.2 

30.71 

613 

.6 

20.65    9794 

.6 

25.38    4386 

A 

30.82 

714 

•8 

20.73 

9693 

.8 

25.49    4272 

.6 

30.93 

-  813 

J.    C.    SAL  A,    SAN    FRANCISCO 


TABLE, 


THERMOMETERS. 

Corresponding  Temperatures  by  the  Fahrenheit,  Centigrade 

and  Reaumur  Scales. 


'  lahren 

.  Centi. 

BflM. 

Fahren 

.  Centi. 

Reau 

Fahren 

.   Centi 

Reau. 

)  212   100.0  ' 

Dag 
80.0 

128* 

53.3"' 

De 
42. 

Deg.  i  Deg 
44     67 

5.3 

\  210    98.9 
)  208    97.8 

79.1 

78.2 

126. 
124 

52.2 
51.1 

41. 
40. 

42 
40 

5.5     4.4 
4.4     3.5 

206    96.7 

77.3 

122 

50.0 

40.0 

38 

3.3     2.6 

204    95.6     76.4 

120 

48.9 

39.1 

36 

2.2 

1  IT 

202    94.4     75.5 

118 

47.8 

38.2 

34 

1.1  •   0.8 

2DO    93.3     74.6 

116 

46.7 

37.3 

32 

0.0      .0  ( 

198    92.2 

73.7 

114 

45.6 

36.4 

30 

-  1.1   -  0.8  ( 

196    91.1 

72,9 

112 

44.4 

35.5 

28 

2.2  i   1.7  ( 

)  194    90.0 

72.0 

110 

43.3 

34.6 

26 

3.3 

2.6  ( 

)  192    88.9 

71.1 

108 

42.2 

33.7 

24 

4.4 

3.5 

)  190    87.8 

7C.2 

106 

41.1 

32.8 

22 

5.5     4.4 

j  188 

86.7 

69.3 

104 

40.0 

32.0 

20   i  -  6.7  .  -  5.3 

186 

85.6 

68.4 

102 

38.9 

31.1 

18 

7.7 

6.1 

184 

84.4 

67.5 

100 

37.8 

30.2 

1C 

8.9 

7.3 

182 

83.3   :   66.6 

98 

36.7 

29.3 

14 

10.0 

8.0 

180 

82.2     65.7 

96 

35.6 

28.4 

12 

11.1  :   8.8 

178    81.1     64.9 

94 

34.4     27.5 

10 

12.2     9.7 

176 

80.0 

64.0 

92 

33.3 

26.6 

8 

-  13.3   -10.6 

174 

78.9 

63.1 

90 

32.2 

25.7 

g 

14.4 

11.5 

172 

77.8 

62.2 

88 

31.1 

24.8 

4 

15.5 

12.4 

170 

76.7     61.3 

86 

30.0 

24.0 

2 

16.7 

13.2 

167 

75.0 

60.0 

84 

28.9 

23.1 

o 

17.7 

14.1 

166 

74.4 

59.5 

82 

27.7 

22.1 

2 

18.9 

15.1 

'  164    73.3     58.6 

80 

26.6 

21.2 

4 

-  20.0 

-16.0 

(  162    72.2 

57.7 

78 

25.5 

20.4 

g 

21.1 

16.8 

160    71.1 

56.8 

77 

25.0 

20.0 

8 

22.2 

17.7 

158 

70-0 

56.0 

74 

23.3 

18.6 

10 

23.3 

18.6 

166 

68.9 

55.1 

72 

22.2 

17.7 

12 

24.4 

19.5 

154    67.8 

54.2 

70 

21.1 

16.8 

14 

25.5    20.4  \ 

152    66.7 

53.3 

68    20.0 

16.0 

16   -  26.7   -21.2  <* 

150    65.6 

52.4 

66 

18.9 

15.1 

8 

27.7 

22.1  ( 

148    64.4 

51.5 

64 

17.7 

14.1 

20 

28.9 

23.1  ( 

146    63.3 

50.6 

62 

16.6 

13.2 

2 

30.0 

24.0  ( 

144    62.2 

49.7 

60 

15.5 

12.4 

4 

31.1 

24.8  > 

142     61.1 

48.8 

58 

14.4 

11.5 

6 

32.2 

25.7  ) 

i 

140 

60.0 

48.0 

56 

13.3 

10.6 

8 

-  33.3   -26.6  ) 

138 

58.9 

47.1 

54 

12.2 

9.7 

0 

34.4    27.5  ) 

136 

57.8 

40.2 

52 

11.1 

8.8 

2 

35.6 

28.4 

134 

56.7 

45.3 

50 

10.0 

8.0 

4 

36.7 

29.3 

132 

55.6 

44.4 

48 

8.9 

7.3 

6 

07.8 

30.2 

130 

54.4 

43.5 

46 

7.7 

6.1      8 

38.9    31.1 

/ 

r66 


ILLUSTRATED    CATALOGUE   OF 


TABLES. 


Equivalents  of  Lineal  Measures. 


^  Inches. 

Links. 

Feet. 

Varas. 

Yards. 

Chains.  |  Miles. 

SjT  Lea. 

Eng,Lea.( 

',   1 

0.12G2G3 

0.083333 

0.029965 

0.027778  0.001263  0.000010 

0.000006 

0.000005  ( 

"7.92 

1 

0.66 

0.237325 

0.22 

0.01    0.001)125 

0.000047 

0.000042  ( 

ia 

)  33.372 

1.515152 
4.213636 

2.781 

0.359583 
1 

0.333333 
0.927 

0.015152  0.000189 
0.042136  0.000527 

0.000072 
0.0002 

0.000063  ( 

0.000176  ; 

\36 

4.545455 

;j 

1.078749    1 

0.045455  0.000568 

0.000216 

0.000189  / 

i792 

100 

66 

23.73247|  22 

1    0.0125 

0.01)4746  0.004167  ) 

',63300 

8000 

5280 

1898.598  1760 

80        1 

0.379720  0.333333  , 

U  66860 

210(58.18 

13905 

5000 

4635    210.6818  2.63H52  i 

1 

0.877841  ' 

'  190383 

24000 

15840 

5695.793 

5280 

240    |3 

1.139159 

1    ( 

Equivalents  of  Square  Measures. 


;   Varas. 

Yards. 

Chains. 

Acres. 

Miles. 

Sp.  League!  Eng.  Lea.  , 

\  i 

0.859329 

0.00177547 

0.00017755 

0.00003328  0.00300304  0.00000303 

"1.16369865 

1 

0.032[>6612 

0.00020661 

O.();)003332 

0.00000005'  0.00000004 

}563.230148 

484 

1 

0.1        0.0001H625 

0.03002253  0.000017o6 

)  5632.30148 
\3604672.95 

4840 
3097600 

10 
6400 

640 

0.0015625 

0.00022533  0.00017361  ) 
0.14418092  0.11111111  ) 

\25000000 

21483225 

44386.8285  '4438.68285 

6.93544195 

1     0.77060466 

^32442056.5 

27878400 

57600     5760 

9 

1.29768226     1 

FrencJi  Units  of  Weights  and  Measures,  &c. 


MKTUIC. 


,     MEASURES  OF  LENGTH. 
)  Myriametre. . .  .10000  meters 

r  Kilometre 1000     " 

(  Hectometre ....    100      •• 

)Dekametre 10      " 

, Metre 1      - 

Decimetre...  one-tenth  " 
1  Centimetre... one  100th  " 
Millimetre.. one  1000th   " 
I  Kilometre  . . .  .3-280.833  feet 
1  Hectometre. . .  .32S.OS3  feet 


GRAMME. 

LlTHK. 

WEIGHTS. 
Millier     .  1000000  Grammes 

MEASUKES  OF  VOLUME. 
Kilolitre  lOOOlitre 

I 
8 

Quintal....  100000 

Hectolitre  100    " 

) 

Myriagram'    10000 
Kilogram'         1000        ** 

Decalitre  10    " 
Litre                      ..      1    " 

I 

Hectogram  '      100        " 

Decilitre  one-tenth    " 

? 

Dekagram'.         10 

Centillitre....  one  100th     " 

( 

( 

Gramme...            1 

Millilitre....  one  1000th    " 

Decigram',  one-tenth     " 

1  Fluid  Dr'in.,0,(ll):'''''-"'7     " 

I 

Centigram.  one  100th     " 

1  Fl.()unc.e...0.02'.i.'."-!'.t     " 

\ 

Milligram'.  one  1000th    " 

1  !•'!.  Found.  0  ;!54S3050      " 

\ 

CUBIC  WEIGHT. 

CUBIC  MEASUKE. 

f 

1  Cubic  M.     2204  (i  Ibs.  A  O 

1  Cub.M.  ..204.17  wiiu-ga 

\ 

MEASURE  OF  SUKKACE. 
Hectare...  .10000  Sq.  Meters 

Hectarc 2.471  aeres  1  Cub. Litre,  2.2040   "       "     i  1  Cub.  Litre.l.05G7  wine  gal 

Are..". 119. 0  Sq.  Yards  ,  Tonncau.  .1000000  gr'nni.es. 


J.    C.    SALA,    SAN   FRANCISCO 


I67 


Inches.  |     Links. 


7.92 

12 

36 

7'.)2 


39.37 


0.126263 

1.515152 

4.545455 

100 

8000 

4.9710591 


Inches. 


637364 

'6272640 
,'1550.0581)477 


TABLES. 


Equivalents  Lineal  Measures 


Feet. 


O.OH3333 
0.63 

3 

66 

5280 

3.280899 


Yards.     I     Chains. 


Miles. 

0.000016 

,    ,   0.000125 

0.333333   j   0.015152    '  0.000189 


0.027778  !   0.001263 


(1.22 


(1.01 


1760 
1.093633 


0.045455 


0.0497106  0.0006213 


Meters. 

0.02540005 
0.20116839 
0.3048006 

0.000568  I  0.9144018 
20. 11683!)  6 
1609.347168 
1 


0.0125 
1 


Equivalents  of  Square  Measures. 


Feet. 

0.0069444 

1 
9 

4356 
4356G 
10.7642982 


0.0007716 
10.333333 

484 

4840 

1.11)61331 


Chains. 

0.0000016 
(0.0002296 
10.00206612 

1 
(10 

0.0024711 


Meters. 
0.00000016  0.000645161 


0.9000229 


Equivalents  of  Weights. 


0.1 

0.00024711 


0.092903184 


404.671063 
4046.71063 
1 


<i  rains. 


60 

480 
)437.5 
S6760 
$7000 
(15.43316 


Scruples.  Drachms.    Ox.  Troy. 


0.05 


24 

21.875 

288 

d50 

0.771658 


0.016666 
0.333333 


7.18311 

96.00 

116.66 

0.257219    0.032151 


0.002083 
0.041666 
0.125 

1.0098 

12 

14.5833 


Oz.  A.D. 

0.002285 
0.045714 
0.139215 
0.990295 

13.168 

16 

0.035275 


P'd  Troy.!  P'd  A.D. 


0.000173 

0.003472 

1  0.310416 

I  0.083333 

0.075;)41 

1.215278 
1  0.002679 


0.000142 

0.002857 

0.008571 

0.0685702 

0.0625 

0.822857 


Grammes/ 

0.648004  ) 
1.296008 
3.888024 
31.10419  \ 
28.35017  ( 
373.2502  ( 
453.6028  ( 
1         ( 


Equivalents  of  Liquid  Measures. 


Gills. 

1        Pints. 

Quarts. 

Gallons. 

0.03125 
0.125 
0.25 

0.2641407 

Liters. 

Cubic  Inches,  > 

7.21875           ^ 
28.875             S 
57.75 
231. 
61.0165           ( 

1 

2 
4524 

'0.25    ^ 

1 
2.1131 

0.125 
0.50 

1.05656 

0.1182955 
0.4737821 
0.9463642 
3.7854579 
1 

A  standard  avoirdupois  pound  is  the  weight  of  27.7015  cubic  inches  of  distilled  ', 

water,  weighed  in  air  at  a  temperature  of  39 . 83  Fahrenheit,  barometer  at  30  inches.  ) 

A  cubic  inch  of  such  water  weighs  252.6037  grains.  ^ 

A  cubic  foot  contains  7.48052  gallons  liquid  measure.  A  gallon  is  equal  to  a  / 

cylinder  of  7  inches  in  diameter  and  6  inches  high.  ( 


INDEX 


A 

PAGE 
78 

Compass   Prismatic 

evel  

5O 

Solar 

lane  Table  

64 

Surveyors'. 

extant  
olar  Compass.  .  .  . 
ransit  

er.    . 

66 
59 
44 
10 

84 

"         Vernier  

D 

Dividing  Kngine,  Automatic. 

jsting  Magnetic) 
[etal                       J 

16 

Dumpy  Level  
Drawing  Materials  .  . 

72 

Instruments  

i  .  . 

6s 

Abney's  Level.  .  .  . 
Adjustment  of  Level 

<  < 

Aluminum  .  . 
Aneroid  Barometer.  . 
Apparatus  for  Testin 
Influence  on  Metal  . 
Arrows  ..... 

Artificial  Ho 

Astronomical  Telescopes  .........  103 

Attachments  of  the  Transit  .......   32 

Automatic  Dividing  Kngine  .......    15 


PAGR 
.  60 

•  57 

•  53 

•  55 


15 
49 
93 
99 


B 

Bags,  Gossamer  and  Silk  ...... 

Barometers,  Aneroid  Surveying.  .  . 
"       Weather  .... 

Mercurial  Standard  .... 

Black  Process  Paper  ........  ...... 

Blue  "      ............. 

Books  on  Engineering  and  Sur-  )_ 
veying  .......................  j 


90 

84 

105 

106 

94 

93 

t 


Brushes  for  Cleaning  Instruments.   90 


Camera  Lucida 90 

Care  of  Instruments 19 

Cases  for         "  13 

Centering  Apparatus 16 

Centers  of  Instruments 27 

Chains.  .  .   73 

Clamps  and  Tangent  Screws 31 

Clinometers,  Attwood 80 

Clinometer  Rule 79 

Cloth  Finish  of  Instruments 12 

Collar  Tester 19 

Collimator  Apparatus 17 

Compass  (on  Transit) 30 

"         Clinometer 56 

Pocket 57 

Plain  .         55 


Engineers'  Level.  . . 
Transit. . 

Errors  of  Compass  . 
Extension  Tripods  . 


•  47 

•  36 

•  54 

•  3' 


Field  Books  for  Engineers  and  1 

Surveyors \  - 

Field  Glasses 86 

Finish  of  Instruments 12 

Flexible  Rods.    .  .  72 


Graduations 

Gradienter  Screws 

"          Screw  Tables 

Ground  Bubbles 

H 

Hand  Level 

Heliographs 

Hydrographic  Level 

Hydrometers 

Hygrometers 


Latitude  Coefficients 

Level 


25 

32 

140 

105 


78 
103 

50 
106 
106 


116 
47 


INDKX — CONTINUED 


PAGE 

Level,  Abney's 78 

' '     Architects' 49 

"     Dumpy 49 

' '     Engineers'  Y 48 

1 '     Farmers' 49 

"     Hand 78 

' '     Hydrographic 50 

"     Locke's 78 

' '     Pocket 78 

' '     Rod   90 

1 '     Reversion 50 

"     Sala's  Telescopic  Hand 79 

"     Tape 77 

' '     Trier  

Leveling  Screws 

Rods 

Longitudinal  Dividing  Engine 


Lubricants 90 


M 


89 


Magnifying  Glasses 

Making  and  Repairing  of  Instru-  \ 

ments ) 

Marine  Glasses 86 

Meridian  by  two  equal  Altitudes.  .  142 

Mining  Transit 40 

Mountain  Transit 40 


O 


Odometer,  Sala's  

Offset  Attachment  to  Transit. 
Optical  Square 


81 
39 
67 


Packing  Instruments.  . 

.  .  .    .       14 

Plate  Levels  

.  .    .      .27 

Pantograph  .  . 

.    QS 

Parallel  Rulers 

98 

Passometer  
Pedometer 

81 
Si 

Pins  

73 

Plane  Table  

....     62 

Planimeter. 

QS 

Plumb  Bobs  

82 

Plumet  Lamp,  Sala's  
Pocket  Compass  
"      Level.. 

83 
61 
.    78 

Pocket  Magnifiers 89 

Preface 8 

Protractors 95 

Draughtsmen's 96 

Boxwood 97 

Kern's  Vernier 96 


Rain  Gauges 

Refraction  Table 

Repairing  Instruments 

Rods,  English  self-reading. .  . . 

"      Flexible 

"      Flynn's 

' '      Iron  Tubular 

"      Line 

' '      Metric  . . 

"       New  York 

"      Philadelphia , 

"      Sala's  self-reading 

"  Steel  Line 

Rules,  Stephen's  Combination 

"       Clinometer.. 


Saegmuller's  Solar  Attachment 
Scales,  Flat  and  Triangular.  .  .  . 

<(       Rule 

Sextant,  Marine 

Pocket 

Slide  Rules,  Stadia 

Solar  Attachments 

Spy  Glasses 

Stadia  Surveying 

Standards 

Standard  Steel  Tapes 

Straight  Edges 


T  Squares 

Table  of  Refractions  in  Declina- 
tion for  Solar  Compasses 

Table  of  Increase  or  Decrease  of 
the  Sun's  Declination 

Table  of  Azimuth  of  Polaris 

"  Length  of  a  Degree  of  Lat- 
itude. . 


104 
117 
13 
71 
7i 
72 

7i 
71 
72 

71 
71 
72 

7i 
90 

79 


109 
97 
98 
65 
66 
98 

33 

89 

126 

30 

75 


..   98 
}i44 

}i45 
.  .  146 

}iso 


INDEX — CONTINUED 


rrvvjc 

Table,  Length  of  a  Degree  of) 
Longitude j  5 

Table,  Divergency  of  the  Parallel ) 
of  Latitude !  I54 

Table,  Reducing  Chains  to  Feet.  .  .  155 

of  Acres  required  per  Mile  i 
and  per  100  feet  for  different  L 155 
widths J 

Table,  Trigonometrical  Series 156 

of  Solution  of  Triangles. .  .  .  157 

"       for  Running  Slopes 157 

"       Geographical  Position  of)      o 
Standard  Lines  in  California. .  /  T^ 

Table,  Geographical  Position  of) 
Standard  Lines  in  Nevada.  .  .  .  j  I^9 

Table,  Geographical  Position  of) 
Standard  Lines  in  Utah j  I59 

Table,  Geographical  Position  of\    .- 
Standard  Lines  in  Montana.  .  .  / 

Table,  Geographical  Position  of)    ^ 
Standard  Lines  in  Washington  ) 

Table,  Geographical  Position  of)    ^ 
Standard  Lines  in  Arizona. ...  j' 

Table,  Geographical  Position  of)    , 
Standard  Lines  in  Oregon / 

Table  of  Grades 162 

"      Radii,    Middle    Ordinates,  ) 
etc. ,  of  Curves i 

Table,  Temperature  of  Boiling  | 
Water  corresponding  to  Alti-  > 
tude  J 

Table,  corresponding  Tempera-  j 
tures  by  the  Fahrenheit,  Centi-  , 
grade  and  Reaumur  Therrnom-  j 
eters J 

Table,  Equivalents  of  Lineal ) 
Measures ) 

Table,  Equivalents  of  Square ) 
Measures ) 

Table,  French  Units  of  Weights)  j66 
and  Measures 1 

Table,  Equivalents  of  U.S.  stand- )  j6 
ard  and  Metric  Lineal  Measures  ) 


163 


164 


165 


166 


1 66 


Table,  Equivalents  of  U.S.  stand-  )    , 
ard  and  Metric  Square  Measures  j  l   ' 
Table,  Equivalents  of  U.S.  stand-  )    , 
ard  and  Metric  Liquid  Measures  j      ' 

Tangent  Screws  and  Clamps 31 

Tapes,  Chesterman's 74 

Eddy's 75 

"        Metallic  Warp 77 

Paine's 75 

Rival 76 

Telemeter 67 

Telescope 29 

Astronomical 103 

Binocular 88 

Aluminum   88 

Thermometers 106 

Thumb  Tacks 93 

Timber  Scriber 90 

Topographical  Surveying 120 

Tracing  Cloth 93 

Paper -93 

Transit  (description) 25 


Solar . 


combined  Mining  and 


39,  40 


Transit,  Engineers' 34,  36>  37 

"        Light  Mountain 42 

"        Small  Mining 43 

"        Surveyors' 38 

Transportation  of  Instruments 14 

Triangles 98 

Tripods •            •  31 

"      Sala's  Extension 105 

•<      Attachment 29 


Verniers 

Variation  Arc 


25 
39 


77231 


THE  UNIVERSITY  OF  CAUFORNIA  LIBRARY 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  SO  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


OCT    17  1933 


217 


The  Above  Cut  Represents  the  Mining-  Transit  as  Used  with 
Saeg-muller's    Solar   Attachment. 


tl, ill 


J.    C. 

429  Montgomery  Street, 


San   Francisco,  Cal. 


